How to Choose the Right Size Water Tank for Your Home or Business in Karachi

Water is essential for life, but it is also a scarce and precious resource in many parts of the world. In Karachi, the largest and most populous city in Pakistan, water scarcity is a serious and chronic problem that affects millions of people every day. According to a report by the World Bank, Karachi faces a water deficit of 50 percent, meaning that the city’s water supply is only half of its demand. This situation leads to frequent water shortages, rationing, and contamination, which pose significant health, economic, and social challenges for the residents and businesses of Karachi.

One of the ways to cope with this water crisis is to install a water tank in your home or business premises. A water tank can store water from various sources, such as municipal supply, groundwater, or rainwater, and provide you with reliable and convenient access to water whenever you need it. However, choosing the right size water tank for your home or business is not a simple task. There are many factors to consider, such as your water usage requirements, roof area and rainfall, available space, budget constraints, future growth and expansion, water quality and purity, legal and regulatory considerations, water tank types, maintenance and care, eco-friendly options, and supplier selection.

In this article, we will guide you through these factors and help you make an informed decision on how to choose the right size water tank for your home or business in Karachi.

Factors to Consider When Choosing a Water Tank Size

Water Usage Requirements

The first and most important factor to consider when choosing a water tank size is your water usage requirements. This refers to how much water you need for your daily activities or operations. The water usage requirements vary depending on whether you are using the water tank for residential or commercial purposes.

Residential

For residential purposes, the water usage requirements depend on the number of people living in your household, the type and frequency of activities that require water, such as drinking, cooking, washing, bathing, gardening, etc., and the level of water conservation that you practice. According to the Pakistan Council of Research in Water Resources (PCRWR), the average per capita water consumption in urban areas of Pakistan is about 114 liters per day.

However, this figure may vary depending on your lifestyle and preferences. For example, if you have a large family, use water-intensive appliances such as washing machines or dishwashers, or have a lush garden or lawn that needs regular watering, you may need more water than the average. On the other hand, if you have a small family, use water-efficient appliances or fixtures such as low-flow showerheads or faucets, or have a drought-tolerant garden or lawn that needs minimal watering, you may need less water than the average.

To estimate your residential water usage requirements, you can use the following formula:

Water usage requirements (liters per day) = Number of people x Average per capita consumption

For example, if you have a family of five people and your average per capita consumption is 114 liters per day, your water usage requirements would be:

Water usage requirements = 5 x 114 = 570 liters per day

Commercial

For commercial purposes, the water usage requirements depend on the nature and scale of your business activities that require water, such as manufacturing, processing, cleaning, cooling, heating, irrigation, etc., and the level of water efficiency that you implement. According to the International Water Association (IWA), the average per capita water consumption in commercial sectors ranges from 50 to 250 liters per day. However, this figure may vary depending on your industry and operations. For example, if you run a restaurant, a hotel, a laundry service, or a car wash, you may need more water than the average. On the other hand, if you run an office, a shop, a salon, or a clinic, you may need less water than the average.

To estimate your commercial water usage requirements, you can use the following formula:

Water usage requirements (liters per day) = Number of employees x Average per capita consumption + Additional consumption for specific activities

For example, if you run a restaurant with 20 employees and your average per capita consumption is 200 liters per day, and you also need an additional 1000 liters per day for cooking, washing dishes, and cleaning tables, your water usage requirements would be:

Water usage requirements = 20 x 200 + 1000 = 5000 liters per day

Roof Area and Rainfall

The second factor to consider when choosing a water tank size is your roof area and rainfall. This refers to how much rainwater you can collect from your roof and store in your water tank. Rainwater harvesting is a sustainable and cost-effective way to supplement your water supply and reduce your dependence on the municipal system or groundwater sources. Rainwater is also generally clean and pure and can be used for various purposes, such as drinking, cooking, washing, bathing, gardening, etc., with minimal or no treatment.

To estimate how much rainwater you can collect from your roof, you can use the following formula:

Rainwater collection potential (liters per year) = Roof area (square meters) x Rainfall (millimeters per year) x Runoff coefficient

The roof area is the horizontal projection of your roof, which can be measured by multiplying the length and width of your roof. The rainfall is the average annual rainfall in your location, which can be obtained from the Pakistan Meteorological Department (PMD). The runoff coefficient is a factor that accounts for the losses due to evaporation, infiltration, and leakage from your roof and gutters. The runoff coefficient varies depending on the type and slope of your roof, but it usually ranges from 0.7 to 0.9 for most roofs.

For example, if you have a flat concrete roof with an area of 100 square meters and the average annual rainfall in Karachi is 250 millimeters per year, and you assume a runoff coefficient of 0.8, your rainwater collection potential would be:

Rainwater collection potential = 100 x 250 x 0.8 = 20000 liters per year

Available Space

The third factor to consider when choosing a water tank size is your available space. This refers to how much space you have in your property to install and accommodate your water tank. The available space depends on the shape and dimensions of your water tank, as well as the location and orientation of your water tank. The shape and dimensions of your water tank affect how much water it can store, as well as how much space it occupies. The location and orientation of your water tank affect how easy or difficult it is to access, maintain, and connect to your plumbing system.

The most common shapes of water tanks are cylindrical, rectangular, and spherical. Cylindrical tanks are usually horizontal or vertical and have a circular cross-section. Rectangular tanks are usually box-shaped and have a rectangular cross-section. Spherical tanks are usually dome-shaped and have a spherical cross-section. Each shape has its own advantages and disadvantages, depending on your available space and preferences.

Cylindrical tanks are the most popular shape of water tanks because they are easy to manufacture, transport, install, and maintain. They also have a high volume-to-surface-area ratio, which means that they can store more water with less surface area exposed to the environment. This reduces the heat loss or gain, evaporation, contamination, and algae growth in the water tank.

However, cylindrical tanks also have some drawbacks, such as requiring more space than rectangular or spherical tanks for the same volume of water, having more stress on the walls due to the internal pressure of the water, and being more prone to rolling or tipping over if not properly secured.

Rectangular tanks are another common shape of water tanks, because they are easy to fit into corners or along walls, where space is limited or irregular. They also have a low height-to-width ratio, which means that they can be installed in places where the vertical clearance is low, such as basements or attics. However, rectangular tanks also have some drawbacks, such as having a low volume-to-surface-area ratio, which means that they store less water with more surface area exposed to the environment. This increases the heat loss or gain, evaporation, contamination, and algae growth in the water tank. Moreover, rectangular tanks have more stress on the corners due to the internal pressure of the water, and may require additional reinforcement or bracing.

Spherical tanks are the least common shape of water tanks, because they are difficult to manufacture, transport, install, and maintain. They also have a high height-to-width ratio, which means that they require more vertical clearance than cylindrical or rectangular tanks for the same volume of water. However, spherical tanks also have some advantages, such as having a high volume-to-surface-area ratio, which means that they store more water with less surface area exposed to the environment. They also have less stress on the walls due to the internal pressure of the water, and are more stable and resistant to rolling or tipping over.

The location and orientation of your water tank depend on whether you choose an underground or overhead water tank. Underground water tanks are installed below the ground level, usually in basements or backyards. Overhead water tanks are installed above the ground level, usually on rooftops or terraces.

Underground water tanks have some advantages over overhead water tanks, such as being hidden from sight, protected from extreme weather conditions, and maintaining a constant temperature and pressure. However, underground water tanks also have some disadvantages, such as being difficult to access, inspect, and clean, requiring excavation and waterproofing, and being vulnerable to groundwater contamination and leakage.

Overhead water tanks have some advantages over underground water tanks, such as being easy to access, inspect, and clean, requiring no excavation and waterproofing, and being less prone to groundwater contamination and leakage. However, overhead water tanks also have some disadvantages, such as being visible and unsightly, exposed to extreme weather conditions, and varying in temperature and pressure.

The orientation of your water tank refers to whether you choose a horizontal or vertical cylindrical tank. Horizontal tanks are usually installed on the ground or on low platforms, while vertical tanks are usually installed on high platforms or stands. Horizontal tanks have some advantages over vertical tanks, such as being easier to transport, install, and maintain, requiring less vertical clearance and support structure, and having a lower center of gravity. However, horizontal tanks also have some disadvantages, such as occupying more horizontal space and having a lower water pressure at the outlet. Vertical tanks have some advantages over horizontal tanks, such as occupying less horizontal space and having a higher water pressure at the outlet. However, vertical tanks also have some disadvantages, such as being harder to transport, install, and maintain, requiring more vertical clearance and support structure, and having a higher center of gravity.

To estimate how much space you need for your water tank, you can use the following formulas:

Space required for a cylindrical tank (square meters) = Length x Diameter

Space required for a rectangular tank (square meters) = Length x Width

Space required for a spherical tank (square meters) = Diameter x Diameter

For example, if you choose a horizontal cylindrical tank with a length of 2 meters and a diameter of 1 meter, the space required for your water tank would be:

Space required = 2 x 1 = 2 square meters

Budget Constraints

The fourth factor to consider when choosing a water tank size is your budget constraints. This refers to how much money you can afford to spend on your water tank purchase, installation, and maintenance. The budget constraints depend on the cost of your water tank, as well as the cost of other related expenses, such as transportation, plumbing, filtering, treatment, permitting, regulation, inspection, cleaning, repair, etc.

The cost of your water tank depends on the size, shape, material, and quality of your water tank. The size of your water tank affects how much water it can store, and therefore how much it costs. The shape of your water tank affects how much space it occupies, and therefore how much it costs. The material of your water tank affects how durable, resistant, and eco-friendly it is, and therefore how much it costs. The quality of your water tank affects how well it performs, how long it lasts, and how safe it is, and therefore how much it costs.

The cost of other related expenses depends on the location, orientation, type, and condition of your water tank. The location of your water tank affects how easy or difficult it is to transport, install, and connect to your plumbing system, and therefore how much it costs. The orientation of your water tank affects how stable and secure it is, and therefore how much it costs. The type of your water tank affects how much filtering and treatment it requires, and therefore how much it costs. The condition of your water tank affects how often it needs inspection, cleaning, and repair, and therefore how much it costs.

To estimate how much money you need for your water tank project, you can use the following formula:

Total cost (rupees) = Cost of water tank + Cost of transportation + Cost of installation + Cost of plumbing + Cost of filtering + Cost of treatment + Cost of permitting + Cost of regulation + Cost of inspection + Cost of cleaning + Cost of repair

For example,

if you choose a plastic horizontal cylindrical tank with a capacity of 1000 liters that costs 10 rupees per liter,

the transportation cost is 1000 rupees,

the installation cost is 2000 rupees,

the plumbing cost is 3000 rupees,

the filtering cost is 1000 rupees per year,

the treatment cost is 500 rupees per year,

the permitting cost is 500 rupees,

the regulation cost is 500 rupees per year,

the inspection cost is 500 rupees per year,

the cleaning cost is 1000 rupees per year,

and the repair cost is 1000 rupees per year,

the total cost for your water tank project would be:

Total cost = 10000 + 1000 + 2000 + 3000 + 1000 + 500 + 500 + 500 + 500 + 1000 + 1000 = 23000 rupees

This is the initial cost for the first year. For the subsequent years, you need to add the annual costs of filtering, treatment, regulation, inspection, cleaning, and repair, which would be:

Annual cost = 1000 + 500 + 500 + 500 + 1000 + 1000 = 4500 rupees

Therefore, the total cost for the second year would be:

Total cost = 23000 + 4500 = 27500 rupees

And so on for the following years.

Future Growth and Expansion

The fifth factor to consider when choosing a water tank size is your future growth and expansion. This refers to how much your water usage requirements may increase or decrease in the future, due to changes in your family size, business scale, lifestyle, preferences, etc. Future growth and expansion affect how much water you will need to store in your water tank, and therefore how big your water tank should be.

To estimate your future growth and expansion, you can use the following formula:

Future water usage requirements (liters per day) = Current water usage requirements x Growth rate

The current water usage requirements are the same as the ones you calculated in the first factor. The growth rate is a percentage that reflects how much your water usage requirements may change over time. The growth rate can be positive or negative, depending on whether you expect your water usage requirements to increase or decrease in the future. The growth rate can be estimated based on your past trends, current plans, or future projections.

For example,

if your current water usage requirements are 5,000 liters per day,

and you expect your water usage requirements to increase by 10% per year,

your growth rate would be:

Growth rate = 10%

Your future water usage requirements for the next year would be:

Future water usage requirements = 5000 x 1.1 = 5500 liters per day

Your future water usage requirements for the next five years would be:

Future water usage requirements = 5000 x (1.1)^5 = 8052.55 liters per day

Your future water usage requirements for the next ten years would be:

Future water usage requirements = 5000 x (1.1)^10 = 12968.97 liters per day

Understanding Water Tank Capacities

The sixth factor to consider when choosing a water tank size is your understanding of water tank capacities. This refers to how much water your water tank can actually store and provide, based on its nominal capacity, effective capacity, and reserve capacity. Understanding water tank capacities is important because it helps you avoid overestimating or underestimating how much water you have in your water tank, and therefore how often you need to refill or empty it.

The nominal capacity of your water tank is the theoretical maximum amount of water that your water tank can hold, based on its dimensions and shape. The nominal capacity is usually expressed in liters or gallons, and it is often indicated on the label or specification sheet of your water tank.

The effective capacity of your water tank is the actual amount of water that your water tank can provide, based on its inlet and outlet positions and heights. The effective capacity is usually less than the nominal capacity, because some of the water in your water tank may not be accessible or usable due to gravity or pressure limitations. The effective capacity is usually expressed as a percentage of the nominal capacity, and it depends on the type and orientation of your water tank.

The reserve capacity of your water tank is the amount of water that you keep in your water tank as a backup or emergency supply, in case of unexpected interruptions or shortages in your main source of water. The reserve capacity is usually more than zero, because it is wise to have some extra water in your water tank for safety and convenience reasons. The reserve capacity is usually expressed as a percentage of the effective capacity, and it depends on your personal preference and risk tolerance.

To calculate the nominal capacity of your cylindrical, rectangular, or spherical water tank, you can use the following formulas:

Nominal capacity of a cylindrical tank (liters) = Length x Pi x Radius^2 x 1000

Nominal capacity of a rectangular tank (liters) = Length x Width x Height x 1000

Nominal capacity of a spherical tank (liters) = Pi x Radius^3 x (4/3) x 1000

To calculate the effective capacity of your horizontal or vertical cylindrical water tank, you can use the following formulas:

Effective capacity of a horizontal cylindrical tank (%) = (Height – Outlet height) / Height x 100

Effective capacity of a vertical cylindrical tank (%) = (Radius – Outlet height) / Radius x 100

To calculate the reserve capacity of your water tank, you can use the following formula:

Reserve capacity (%) = Reserve volume / Effective volume x 100

For example,

if you have a horizontal cylindrical water tank with a length of 2 meters, a diameter of 1 meter, an inlet height of 0.9 meters, and an outlet height of 0.1 meters, and you want to keep a reserve volume of 100 liters in your water tank, the nominal, effective, and reserve capacities of your water tank would be:

Nominal capacity = 2 x Pi x 0.5^2 x 1000 = 1570.8 liters

Effective capacity = (1 – 0.1) / 1 x 100 = 90%

Effective volume = 1570.8 x 0.9 = 1413.72 liters

Reserve capacity = 100 / 1413.72 x 100 = 7.07%

Therefore, your water tank can actually store and provide up to 1313.72 liters of water, and you should always keep at least 100 liters of water in your water tank as a backup or emergency supply.

Assessing Water Quality and Purity

The seventh factor to consider when choosing a water tank size is your assessment of water quality and purity. This refers to how clean and safe your water is for your intended purposes, such as drinking, cooking, washing, bathing, gardening, etc. Water quality and purity affect how much filtering and treatment you need to apply to your water before or after storing it in your water tank, and therefore how big your water tank should be.

To assess your water quality and purity, you need to test your water for various parameters, such as pH, turbidity, hardness, dissolved solids, dissolved oxygen, bacteria, viruses, parasites, chemicals, metals, etc. These parameters indicate how acidic or alkaline, clear or cloudy, soft or hard, pure or impure, fresh or stale, healthy or harmful your water is. You can test your water using various methods, such as litmus paper, colorimetric kits, electronic meters, laboratory analysis, etc.

The acceptable levels of these parameters depend on the standards and guidelines set by the relevant authorities and organizations in your location and industry. For example, in Pakistan, the National Environmental Quality Standards (NEQS) for drinking water are based on the World Health Organization (WHO) guidelines, and they specify the maximum permissible limits for various parameters, such as pH (6.5-8.5), turbidity (5 NTU), hardness (500 mg/L), dissolved solids (1000 mg/L), dissolved oxygen (6 mg/L), bacteria (0 CFU/100 mL), viruses (0 PFU/100 mL), parasites (0 cysts/L), chemicals (various), metals (various), etc.

To improve your water quality and purity, you need to filter and treat your water before or after storing it in your water tank. Filtering is the process of removing solid particles, such as dirt, sand, sediment, rust, etc., from your water using physical barriers, such as screens, meshes, cartridges, membranes, etc. Treatment is the process of removing dissolved substances, such as minerals, gases, organic matter, microorganisms, etc., from your water using chemical or biological agents, such as chlorine, ozone, UV light, activated carbon, reverse osmosis, etc.

The type and degree of filtering and treatment that you need depend on the source and quality of your water, as well as the purpose and preference of your use. For example,

if you use municipal water for drinking,

you may need to filter it for turbidity and treat it for chlorine residual.

If you use groundwater for washing,

you may need to filter it for hardness and treat it for iron.

If you use rainwater for gardening,

you may need to filter it for debris and treat it for acidity.

The size of your water tank affects how much filtering and treatment you need,

because the longer you store your water in your water tank,

the more likely it is to deteriorate in quality and purity due to factors such as temperature, light, air, biological growth, chemical reactions, etc. Therefore, you may need to adjust your filtering and treatment methods and frequencies according to the size of your water tank.

To calculate how much filtering and treatment you need for your water tank,

you can use the following formula:

Filtering and treatment requirements (liters per day) = Water usage requirements x Filtering and treatment factor

The water usage requirements are the same as the ones you calculated in the first factor.

The filtering and treatment factor is a number that reflects how much filtering and treatment you need to apply to your water per liter.

The filtering and treatment factor varies depending on the type and degree of filtering and treatment that you use,

but it usually ranges from 0.01 to 0.1 for most methods.

For example,

if your water usage requirements are 5000 liters per day,

and you use a simple carbon filter and a chlorine tablet for your water,

your filtering and treatment factor would be:

Filtering and treatment factor = 0.05

Your filtering and treatment requirements would be:

Filtering and treatment requirements = 5000 x 0.05 = 250 liters per day

This means that you need to filter and treat 250 liters of water per day to meet your water quality and purity standards.

Legal and Regulatory Considerations

The eighth factor to consider when choosing a water tank size is your legal and regulatory considerations. This refers to the rules and regulations that govern the installation and operation of your water tank in your location and industry. Legal and regulatory considerations affect how much permitting and compliance you need to obtain and maintain for your water tank, and therefore how big your water tank should be.

To comply with the legal and regulatory considerations, you need to obtain the necessary permits and approvals from the relevant authorities and organizations in your location and industry, such as the municipal corporation, the water board, the environmental protection agency, the fire department, the health department, etc. These permits and approvals may include building permits, plumbing permits, electrical permits, water connection permits, water quality certificates, fire safety certificates, health safety certificates, etc.

The requirements and procedures for obtaining these permits and approvals vary depending on the size, shape, material, type, location, orientation, and purpose of your water tank. For example,

• If you install an underground water tank in your backyard, you may need to obtain a building permit from the municipal corporation, a water connection permit from the water board, a water quality certificate from the environmental protection agency, and a health safety certificate from the health department.
• If you install an overhead water tank on your rooftop, you may need to obtain a building permit from the municipal corporation, a plumbing permit from the water board, a fire safety certificate from the fire department, and a health safety certificate from the health department.
• If you install a plastic horizontal cylindrical tank with a capacity of 1000 liters for residential purposes, you may need to obtain fewer permits and approvals than if you install a concrete vertical cylindrical tank with a capacity of 2000 liters for commercial purposes.

To estimate how much permitting and compliance you need for your water tank project, you can use the following formula:

Permitting and compliance requirements (number of permits or approvals) = Size factor x Shape factor x Material factor x Type factor x Location factor x Orientation factor x Purpose factor

The size factor is a number that reflects how many permits or approvals you need based on the capacity of your water tank. The size factor usually increases as the capacity of your water tank increases, but it may also depend on the minimum or maximum limits set by the authorities or organizations.

The shape factor is a number that reflects how many permits or approvals you need based on the shape of your water tank. The shape factor usually varies depending on the complexity or simplicity of your water tank shape, but it may also depend on the preferences or restrictions set by the authorities or organizations.

The material factor is a number that reflects how many permits or approvals you need based on the material of your water tank. The material factor usually varies depending on the durability, resistance, and eco-friendliness of your water tank material, but it may also depend on the standards or guidelines set by the authorities or organizations.

The type factor is a number that reflects how many permits or approvals you need based on the type of your water tank. The type factor usually varies depending on the filtering and treatment requirements of your water tank type, but it may also depend on the specifications or regulations set by the authorities or organizations.

The location factor is a number that reflects how many permits or approvals you need based on the location of your water tank. The location factor usually varies depending on the accessibility, visibility, and security of your water tank location, but it may also depend on the zoning or planning rules set by the authorities or organizations.

The orientation factor is a number that reflects how many permits or approvals you need based on the orientation of your water tank. The orientation factor usually varies depending on the stability, support, and pressure of your water tank orientation, but it may also depend on the design or engineering principles set by the authorities or organizations.

A purpose factor is a number that reflects how many permits or approvals you need based on the purpose of your water tank. The purpose factor usually varies depending on the quality and purity standards of your water tank purpose, but it may also depend on the expectations or requirements set by the authorities or organizations.

For example, if you have a plastic horizontal cylindrical tank with a capacity of 1000 liters for residential purposes, your permitting and compliance requirements would be:

Permitting and compliance requirements = 1 x 1 x 1 x 1 x 1 x 1 x 1 = 1

This means that you only need one permit or approval for your water tank project, which could be a water connection permit from the water board.

If you have a concrete vertical cylindrical tank with a capacity of 2000 liters for commercial purposes, your permitting and compliance requirements would be:

Permitting and compliance requirements = 2 x 2 x 2 x 2 x 2 x 2 x 2 = 128

This means that you need 128 permits or approvals for your water tank project, which could include building permits, plumbing permits, electrical permits, water quality certificates, fire safety certificates, health safety certificates, etc.

Popular Water Tank Types

The ninth factor to consider when choosing a water tank size is your knowledge of popular water tank types. This refers to the common and widely used types of water tanks in your location and industry, such as underground water tanks, overhead water tanks, plastic tanks, concrete tanks, insulated tanks, non-insulated tanks, etc. Knowing the popular water tank types can help you compare and contrast their features and benefits, and choose the best one for your needs and preferences.

The most popular water tank types are underground water tanks, overhead water tanks, plastic tanks, concrete tanks, insulated tanks, and non-insulated tanks. Each type has its own advantages and disadvantages, depending on your available space, budget constraints, future growth and expansion, water quality and purity, legal and regulatory considerations, maintenance and care, eco-friendly options, and supplier selection.

Underground Water Tanks

Underground water tanks are water tanks that are installed below the ground level, usually in basements or backyards. Underground water tanks have some advantages over other types of water tanks, such as:

• They are hidden from sight, which means that they do not affect the aesthetics or appearance of your property.
• They are protected from extreme weather conditions, such as heat, cold, rain, wind, etc., which means that they do not suffer from thermal expansion or contraction, corrosion, or damage.
• They maintain a constant temperature and pressure, which means that they do not lose or gain heat or water due to evaporation or condensation.

However, underground water tanks also have some disadvantages over other types of water tanks, such as:

• They are difficult to access, inspect, and clean, which means that they require more professional assistance and equipment for maintenance and care.
• They require excavation and waterproofing, which means that they involve more labor and material costs for installation and operation.
• They are vulnerable to groundwater contamination and leakage, which means that they pose more risks to your health and environment.

Overhead Water Tanks

Overhead water tanks are water tanks that are installed above the ground level, usually on rooftops or terraces. Overhead water tanks have some advantages over other types of water tanks, such as:

• They are easy to access, inspect, and clean, which means that they require less professional assistance and equipment for maintenance and care.
• They require no excavation and waterproofing, which means that they involve less labor and material costs for installation and operation.
• They are less prone to groundwater contamination and leakage, which means that they pose less risks to your health and environment.

However, overhead water tanks also have some disadvantages over other types of water tanks, such as:

• They are visible and unsightly, which means that they affect the aesthetics or appearance of your property.
• They are exposed to extreme weather conditions, such as heat, cold, rain, wind, etc., which means that they suffer from thermal expansion or contraction, corrosion, or damage.
• They vary in temperature and pressure, which means that they lose or gain heat or water due to evaporation or condensation.

Plastic Tanks

Plastic tanks are water tanks that are made of plastic materials, such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), etc. Plastic tanks have some advantages over other types of water tanks, such as:

• They are lightweight and flexible, which means that they are easy to transport, install, and adjust.
• They are durable and resistant, which means that they do not rust, crack, or dent.
• They are eco-friendly and recyclable, which means that they do not harm the environment or waste resources.

However, plastic tanks also have some disadvantages over other types of water tanks,

such as:

• They are susceptible to UV degradation and chemical reactions, which means that they may lose their strength or color over time.
• They are prone to algae growth and bacterial contamination, which means that they may affect the quality and purity of your water.
• They are flammable and combustible, which means that they may pose fire hazards or explosions.

Concrete Tanks

Concrete tanks are water tanks that are made of concrete materials, such as cement, sand, gravel, etc. Concrete tanks have some advantages over other types of water tanks, such as:

• They are strong and stable, which means that they can withstand high pressure and load.
• They are inert and neutral, which means that they do not react with water or chemicals.
• They are customizable and adaptable, which means that they can be shaped and sized according to your needs and preferences.

However, concrete tanks also have some disadvantages over other types of water tanks, such as:

• They are heavy and rigid, which means that they are difficult to transport, install, and adjust.
• They are porous and permeable, which means that they may leak or absorb water or contaminants.
• They are expensive and wasteful, which means that they involve more labor and material costs for installation and operation.

Insulated Tanks

Insulated tanks are water tanks that are covered with insulation materials, such as foam, fiber, rubber, etc. Insulated tanks have some advantages over other types of water tanks, such as:

• They reduce heat loss or gain, which means that they maintain a constant temperature and pressure in your water tank.
• They prevent evaporation or condensation, which means that they conserve water and prevent waterlogging or flooding in your property.
• They protect from external factors, such as noise, dust, insects, etc., which means that they improve the quality and purity of your water.

However, insulated tanks also have some disadvantages over other types of water tanks, such as:

• They increase the size and weight of your water tank, which means that they require more space and support for installation and operation.
• They add to the cost and complexity of your water tank, which means that they involve more labor and material costs for installation and operation.
• They require more maintenance and care, which means that they need to be cleaned, repaired, or replaced regularly.

Non-Insulated Tanks

Non-insulated tanks are water tanks that are not covered with insulation materials. Non-insulated tanks have some advantages over other types of water tanks, such as:

• They reduce the size and weight of your water tank, which means that they require less space and support for installation and operation.
• They simplify the cost and complexity of your water tank, which means that they involve less labor and material costs for installation and operation.
• They require less maintenance and care, which means that they need to be cleaned, repaired, or replaced less frequently.

However, non-insulated tanks also have some disadvantages over other types of water tanks, such as:

• They increase heat loss or gain, which means that they vary in temperature and pressure in your water tank.
• They allow evaporation or condensation, which means that they waste water and cause waterlogging or flooding in your property.
• They are exposed to external factors, such as noise, dust, insects, etc., which means that they affect the quality and purity of your water.

Maintenance and Care

The tenth factor to consider when choosing a water tank size is your maintenance and care. This refers to the regular and periodic actions that you need to take to keep your water tank in good condition and performance. Maintenance and care affect how long your water tank lasts and how well it serves your needs and preferences.

To maintain and care for your water tank, you need to perform the following actions:

• Cleaning and disinfection: This is the process of removing dirt, sediment, algae, bacteria, viruses, parasites, chemicals, metals, etc. from your water tank using physical or chemical methods, such as scrubbing, flushing, draining, chlorinating, ozonating, etc. Cleaning and disinfection are important because they prevent the deterioration and contamination of your water quality and purity, as well as the damage and corrosion of your water tank material. You should clean and disinfect your water tank at least once a year, or more often if you notice any signs of fouling or infection in your water tank.
• Regular inspection: This is the process of checking the condition and performance of your water tank using visual or instrumental methods, such as looking, measuring, testing, etc. Regular inspection is important because it helps you detect and diagnose any problems or issues in your water tank, such as leaks, cracks, dents, rust, etc. You should inspect your water tank at least once a year, or more often if you notice any changes or abnormalities in your water tank.
• Repairs and leak prevention: This is the process of fixing or preventing any defects or damages in your water tank using mechanical or chemical methods, such as sealing, patching, welding, coating, etc. Repairs and leak prevention are important because they restore or improve the functionality and durability of your water tank, as well as conserve water and prevent waterlogging or flooding in your property. You should repair or prevent any leaks or damages in your water tank as soon as possible, or before they worsen or spread.

The size of your water tank affects how much maintenance and care you need, because the larger your water tank is, the more likely it is to accumulate dirt, sediment, algae, bacteria, viruses, parasites, chemicals, metals, etc., and to develop leaks, cracks, dents, rust, etc.

Therefore, you may need to adjust your maintenance and care methods and frequencies according to the size of your water tank.

To calculate how much maintenance and care you need for your water tank, you can use the following formula:

Maintenance and care requirements (hours per year) = Size factor x Shape factor x Material factor x Type factor x Location factor x Orientation factor

The size factor is a number that reflects how many hours of maintenance and care you need based on the capacity of your water tank. The size factor usually increases as the capacity of your water tank increases, but it may also depend on the minimum or maximum limits set by the authorities or organizations.

The shape factor is a number that reflects how many hours of maintenance and care you need based on the shape of your water tank. The shape factor usually varies depending on the complexity or simplicity of your water tank shape, but it may also depend on the preferences or restrictions set by the authorities or organizations.

The material factor is a number that reflects how many hours of maintenance and care you need based on the material of your water tank. The material factor usually varies depending on the durability, resistance, and eco-friendliness of your water tank material, but it may also depend on the standards or guidelines set by the authorities or organizations.

The type factor is a number that reflects how many hours of maintenance and care you need based on the type of your water tank. The type factor usually varies depending on the filtering and treatment requirements of your water tank type, but it may also depend on the specifications or regulations set by the authorities or organizations.

The location factor is a number that reflects how many hours of maintenance and care you need based on the location of your water tank. The location factor usually varies depending on the accessibility, visibility, and security of your water tank location, but it may also depend on the zoning or planning rules set by the authorities or organizations.

The orientation factor is a number that reflects how many hours of maintenance and care you need based on the orientation of your water tank. The orientation factor usually varies depending on the stability, support, and pressure of your water tank orientation, but it may also depend on the design or engineering principles set by the authorities or organizations.

For example, if you have a plastic horizontal cylindrical water tank with a capacity of 1000 liters for residential purposes, your maintenance and care requirements would be:

Maintenance and care requirements = 1 x 1 x 1 x 1 x 1 x 1 = 1 hour per year

This means that you only need one hour of maintenance and care for your water tank per year, which could include cleaning, disinfection, inspection, and repair.

If you have a concrete vertical cylindrical tank with a capacity of 2000 liters for commercial purposes, your maintenance and care requirements would be:

Maintenance and care requirements = 2 x 2 x 2 x 2 x 2 x 2 = 64 hours per year

This means that you need 64 hours of maintenance and care for your water tank per year, which could include cleaning, disinfection, inspection, and repair.

Eco-Friendly Water Tank Options

The eleventh factor to consider when choosing a water tank size is your eco-friendly water tank options. This refers to the ways that you can reduce the environmental impact of your water tank project, such as by using renewable or recycled materials, saving or reusing water, reducing or offsetting emissions, etc. Eco-friendly water tank options affect how much you contribute to the sustainability and conservation of water resources and the environment.

To implement eco-friendly water tank options, you can consider the following methods:

• Rainwater harvesting: This is the method of collecting and storing rainwater from your roof or other surfaces, and using it for various purposes, such as drinking, cooking, washing, bathing, gardening, etc. Rainwater harvesting is eco-friendly because it reduces your dependence on the municipal system or groundwater sources, which are often scarce or polluted. It also reduces your water bills and carbon footprint, as you use less energy and emit less greenhouse gases to pump or treat water. You can implement rainwater harvesting by installing a rainwater tank on your property, along with a gutter system, a filter system, a pump system, and a distribution system.
• Solar-powered pump systems: This is the method of using solar energy to power your water pump systems, which are used to transfer water from your source to your tank, or from your tank to your point of use. Solar-powered pump systems are eco-friendly because they use renewable and clean energy sources, which do not deplete or pollute the environment. They also save you money and energy, as you do not need to pay for electricity or fuel to run your pump systems. You can implement solar-powered pump systems by installing solar panels on your property, along with a battery system, an inverter system, a controller system, and a pump system.
• Water recycling: This is the method of reusing wastewater from your household or business activities, such as washing machines, dishwashers, showers, sinks, toilets, etc., and using it for other purposes that do not require potable water quality standards, such as flushing toilets, irrigating gardens, washing cars, etc. Water recycling is eco-friendly because it reduces your water consumption and wastewater discharge, which are often wasteful or harmful to the environment. It also reduces your water bills and sewage fees, as you use less fresh water and produce less sewage. You can implement water recycling by installing a greywater tank or a blackwater tank in your property, along with a filter system, a treatment system, and a distribution system.

The size of your water tank affects how much you can implement eco-friendly water tank options because the larger your water tank is, the more rainwater you can harvest, the more solar energy you can store, and the more wastewater you can recycle.

Therefore, you may need to adjust your water tank size according to your eco-friendly water tank options. To calculate how much you can implement eco-friendly water tank options for your water tank project, you can use the following formula:

Eco-friendly water tank options (liters per day) = Size factor x Rainwater harvesting factor + Size factor x Solar-powered pump factor + Size factor x Water recycling factor.

The size factor is a number that reflects how much eco-friendly water tank options you can implement based on the capacity of your water tank. The size factor usually increases as the capacity of your water tank increases, but it may also depend on the minimum or maximum limits set by the authorities or organizations.

The rainwater harvesting factor is a number that reflects how much rainwater you can harvest from your roof area and rainfall. The rainwater harvesting factor is usually equal to the rainwater collection potential that you calculated in the second factor.

The solar-powered pump factor is a number that reflects how much solar energy you can store from your solar panel area and sunlight. The solar-powered pump factor is usually equal to the solar power generation potential that you can obtain from the Pakistan Alternative Energy Development Board (AEDB).

The water recycling factor is a number that reflects how much wastewater you can recycle from your household or business activities. The water recycling factor is usually equal to the wastewater generation potential that you can obtain from the Pakistan Environmental Protection Agency (EPA).

For example, if you have a plastic horizontal cylindrical tank with a capacity of 1000 liters for residential purposes, your roof area is 100 square meters, your average annual rainfall is 250 millimeters per year, your runoff coefficient is 0.8, your solar panel area is 10 square meters, your average daily sunlight is 5 hours per day, your solar power generation potential is 150 watts per square meter, your household activities generate 570 liters of wastewater per day, and your wastewater generation potential is 0.8 liters per liter of water used, your eco-friendly water tank options would be:

Eco-friendly water tank options = 1 x (100 x 250 x 0.8) + 1 x (10 x 5 x 150) + 1 x (570 x 0.8) = 20000 + 7500 + 456 = 27956 liters per day

This means that you can implement eco-friendly water tank options that can save or reuse up to 27956 liters of water per day, which is more than enough to meet your water usage requirements of 570 liters per day.

Selecting a Reputable Supplier

The twelfth and final factor to consider when choosing a water tank size is your selection of a reputable supplier. This refers to the company or individual that you choose to buy your water tank from, as well as to provide you with related services, such as transportation, installation, plumbing, filtering, treatment, permitting, regulation, inspection, cleaning, repair, etc. Selecting a reputable supplier is important because it affects the quality and reliability of your water tank project.

To select a reputable supplier, you need to research and compare the local suppliers in your location and industry, such as by visiting their websites, reading their reviews and testimonials, requesting their quotes comparing their prices, etc. You should look for a supplier that has the following qualities:

• Experience and expertise: The supplier should have a long and successful history of providing water tank products and services in your location and industry. The supplier should also have a qualified and skilled team of professionals who can handle all aspects of your water tank project.
• Quality and warranty: The supplier should offer high-quality and durable water tank products that meet or exceed the standards and guidelines set by the relevant authorities and organizations in your location and industry. The supplier should also provide a warranty or guarantee for their water tank products and services that covers any defects or damages that may occur during or after your water tank project.
• Customer service and satisfaction: The supplier should provide excellent customer service and satisfaction that responds to your needs and preferences. The supplier should also provide after-sales support and assistance that helps you with any questions or issues that may arise during or after your water tank project.

The size of your water tank affects how much you need to select a reputable supplier, because the larger your water tank is, the more likely it is to require more products and services from your supplier, and therefore more quality and reliability from your supplier.

Therefore, you may need to adjust your selection criteria according to the size of your water tank.

To calculate how much you need to select a reputable supplier for your water tank project, you can use the following formula:

Selection criteria (points) = Size factor x Experience factor + Size factor x Quality factor + Size factor x Customer service factor

The size factor is a number that reflects how much you need to select a reputable supplier based on the capacity of your water tank. The size factor usually increases as the capacity of your water tank increases, but it may also depend on the minimum or maximum limits set by the authorities or organizations.

An experience factor is a number that reflects how much experience and expertise you expect from your supplier. The experience factor usually ranges from 1 to 5, depending on how complex or simple your water tank project is.

The quality factor is a number that reflects how much quality and warranty you expect from your supplier. The quality factor usually ranges from 1 to 5, depending on how high or low the standards and guidelines are in your location and industry.

The customer service factor is a number that reflects how much customer service and satisfaction you expect from your supplier. The customer service factor usually ranges from 1 to 5, depending on how important or trivial the after-sales support and assistance are for you.

For example, if you have a plastic horizontal cylindrical tank with a capacity of 1000 liters for residential purposes, your water tank project is simple, the standards and guidelines are low, and the after-sales support and assistance are trivial, your selection criteria would be:

Selection criteria = 1 x 1 + 1 x 1 + 1 x 1 = 3 points

This means that you only need to select a supplier that has at least 3 points of experience, quality, and customer service.

If you have a concrete vertical cylindrical tank with a capacity of 2000 liters for commercial purposes, your water tank project is complex, the standards and guidelines are high, and the after-sales support and assistance are important, your selection criteria would be:

Selection criteria = 2 x 5 + 2 x 5 + 2 x 5 = 60 points

This means that you need to select a supplier that has at least 60 points of experience, quality, and customer service.

Conclusion

In conclusion, choosing the right size water tank for your home or business in Karachi is a crucial decision that requires careful consideration of various factors, such as:

• Water usage requirements
• Roof area and rainfall
• Available space
• Budget constraints
• Future growth and expansion
• Understanding water tank capacities
• Assessing water quality and purity
• Legal and regulatory considerations
• Popular water tank types
• Maintenance and care
• Eco-friendly water tank options
• Selecting a reputable supplier

By following the steps and formulas that we have provided in this article, you can estimate and compare these factors and make an informed decision on how to choose the right size water tank for your home or business in Karachi. By doing so, you can ensure reliable and convenient access to water whenever you need it, as well as a sustainable and cost-effective water supply in Karachi.

Additional Resources

If you want to learn more about water tanks or related topics, you can check out the following links to additional resources:

• Pakistan Council of Research in Water Resources (PCRWR)
• Pakistan Meteorological Department (PMD)
• Pakistan Alternative Energy Development Board (AEDB)
• Pakistan Environmental Protection Agency (EPA)
• National Environmental Quality Standards (NEQS) for Drinking Water
• World Health Organization (WHO) Guidelines for Drinking-water Quality