The waterborne diseases that matter most in Karachi are typhoid, hepatitis A and E, cholera, diarrhoeal infections, giardiasis and the rare but deadly Naegleria infection. All of them reach people through water contaminated with sewage or left warm and unchlorinated, and a household’s storage tank is where that contamination collects and multiplies. A tank that is cleaned and disinfected every 6 months removes that reservoir. It does not replace boiling or filtering drinking water, but it cuts the risk from every other use of water in the house.
This guide describes each disease, how it travels from the supply to your family, the signs to act on, and what a clean tank does and does not protect against. It is general information, not medical advice. See a doctor for any illness that worries you.
Why Karachi’s Water Tanks Are Uniquely Vulnerable
1. Intermittent supply
Karachi needs about 1,200 million gallons of water a day and receives about 650 (Geo News). Line water therefore comes for a few hours on set days. Between supplies the pipes stand empty, and empty pipes draw in whatever surrounds them through leaks, including sewage.
2. Water that arrives contaminated
When the Pakistan Council of Research in Water Resources (PCRWR) tested 118 samples from the city in 2017, 107 were unsafe to drink and a third contained E. coli. The researcher leading the study said the E. coli indicated mixing of sewerage and drinking water supplies (Dialogue Earth).
3. Tanker water of unknown origin
Many households buy water. Dawn’s 2023 investigation counted six official hydrants and at least 86 illegal ones (Dawn). The buyer rarely knows which kind filled the tanker, or how clean the tanker and its hose are.
4. Hot rooftop tanks
For most of the year the water in an overhead tank is warm. Chlorine fades quickly and bacteria multiply faster.
5. Ageing underground tanks
Older sumps develop cracks that let in groundwater and seepage from nearby drains. See detecting and preventing leaks.
6. Monsoon flooding
Heavy rain floods streets and sewers, and the mix enters low underground tank covers and cracked supply lines.
The combined effect shows in the numbers. Sindh’s household survey found E. coli in 79.1% of Karachi’s water at source and 85.5% at household level, as reported by Geo News. Water gets more contaminated after it is delivered.
The Most Common Waterborne Diseases in Karachi
| Disease | Cause | Typical time to symptoms | Main symptoms |
|---|---|---|---|
| Typhoid fever | Salmonella Typhi bacteria | 1 to 3 weeks | Fever that climbs over days, headache, stomach pain, weakness |
| Hepatitis A | Hepatitis A virus | 2 to 7 weeks | Tiredness, nausea, dark urine, yellow eyes and skin |
| Hepatitis E | Hepatitis E virus | 2 to 10 weeks | As hepatitis A. Dangerous in pregnancy. |
| Cholera | Vibrio cholerae bacteria | Hours to 5 days | Sudden, profuse watery diarrhoea, vomiting, rapid dehydration |
| Acute diarrhoea and dysentery | E. coli, Shigella, rotavirus and others | 1 to 4 days | Loose stools, cramps, vomiting, sometimes fever or blood in stool |
| Giardiasis | Giardia parasite | 1 to 3 weeks | Prolonged greasy diarrhoea, bloating, weight loss |
| Cryptosporidiosis | Cryptosporidium parasite | 2 to 10 days | Watery diarrhoea lasting 1 to 2 weeks |
| Naegleria infection (PAM) | Naegleria fowleri amoeba | About 1 to 12 days | Severe headache, fever, stiff neck, confusion. Almost always fatal. |
Typhoid fever
Typhoid spreads when water or food is contaminated with the faeces of an infected person. It is the infection most closely tied to Karachi’s water. An outbreak of extensively drug-resistant (XDR) typhoid began in Hyderabad district in November 2016. By December 2018, 5,274 XDR cases had been reported in Sindh, and 69% of them were in Karachi. The strain is resistant to first and second-line antibiotics and to third-generation cephalosporins (WHO).
The WHO’s main recommendations are access to safe water and sanitation, hygiene among food handlers, and typhoid vaccination. The typhoid conjugate vaccine is part of the routine childhood immunisation schedule in Sindh. Ask your doctor about it.
Hepatitis A and hepatitis E
Both are liver infections spread by the faecal-oral route, mainly through contaminated water. Most people recover fully. Hepatitis E is the exception in pregnancy: the WHO states that up to 20 to 25% of pregnant women can die if they get hepatitis E in the third trimester (WHO). A household with a pregnant woman should be especially careful about drinking water.
Cholera
Cholera causes such rapid fluid loss that it can kill within hours if untreated, and it is easily treated with prompt rehydration. Sindh reported 234 laboratory-confirmed cases between 15 January and 27 May 2022. The WHO links cholera mainly to insufficient access to safe drinking water and inadequate sanitation (WHO).
Diarrhoea and dysentery
This is the everyday burden: repeated stomach infections caused by a range of bacteria and viruses. For adults it is usually an unpleasant few days. For small children it can be fatal through dehydration. UNICEF estimates that 53,000 Pakistani children under five die each year from diarrhoea due to poor water and sanitation (UNICEF Pakistan). See how dirty water tanks affect children’s health.
Giardia and Cryptosporidium
These parasites spread through water contaminated with human or animal faeces (CDC). Their cysts are tough. Cryptosporidium in particular survives normal chlorine levels, so boiling or fine filtration is the reliable protection.
Naegleria fowleri
This amoeba lives in warm fresh water and infects only when water goes up the nose, during bathing, swimming or ablution. You cannot get it from swallowing water, and nearly everyone who develops the brain infection dies (CDC). Karachi reports deaths most summers. Health officials say that lack of filtration and chlorination of potable water is a major source of infection and that the germ cannot survive in clean, chlorinated water (Dawn). By July 2026 the city had recorded three deaths in the year (ARY News).
Skin, eye and ear infections
Bathing in heavily contaminated water can cause rashes, infected cuts, conjunctivitis and ear infections, particularly in children and people with weak immunity. Warm stagnant tanks can also harbour Legionella, which infects the lungs through shower spray. See the Legionella threat in Karachi’s water tanks.
How Pathogens Enter and Multiply in Your Water Tank
- They arrive with the water, from line supply that has mixed with sewage or from a tanker.
- They settle in sediment. Silt, rust and organic matter sink to the floor and form sludge, which shelters germs and feeds bacteria.
- They join the biofilm. A slippery film of bacteria grows on the walls within weeks of filling. It protects the organisms inside from chlorine and sheds them back into the water.
- They come through the top, with dust, insects, lizards and bird droppings when a lid is loose. See bird contamination in rooftop tanks.
- They come through the walls of a cracked underground tank.
- They multiply in the heat, or in the case of viruses and parasite cysts, simply survive until someone drinks them.
Chlorine cannot get through sludge and biofilm. Whatever disinfectant is in the water is used up at the surface. That is why a physically dirty tank stays contaminated however much bleach is added. More detail is in bacteria in Karachi’s water tanks and how to combat them.
How Regular Tank Cleaning Prevents Waterborne Disease
| Step | What it does for health |
|---|---|
| Draining and sludge removal | Takes out the sediment where germs collect and bacteria feed |
| Pressure washing | Strips the biofilm off walls, floor and corners |
| Vacuuming out waste water | Removes the loosened dirt instead of leaving it to settle again |
| Chlorine disinfection | Kills the bacteria and viruses left on the cleaned surfaces |
| Rinsing | Removes disinfectant before the tank refills |
| Inspection while empty | Shows cracks, broken lids and missing mesh, so entry points can be closed |
These are the steps our crews follow on every job. See the service procedure and the chemicals we use.
What cleaning cannot do
It cannot change the water that arrives next. If the supply is contaminated, the tank will receive it. The difference is that the new water lands in a disinfected tank and is used within days, instead of topping up months of growth. For drinking, a second barrier is still needed.
The full set of protections
- Clean and disinfect both tanks every 6 months.
- Keep lids sealed and openings meshed.
- Boil drinking water for at least one minute, or use a properly maintained filter. See filtration and cleaning in Karachi homes.
- Wash hands with soap before preparing food and after using the toilet.
- Keep children’s vaccinations up to date, including typhoid and hepatitis A where advised.
- In the hot months, keep the tank chlorinated and avoid forcing water up the nose. Use boiled and cooled water for nasal rinsing.
How Often Should You Clean Your Water Tank in Karachi?
We recommend every 6 months for every house, for the underground and overhead tanks together.
- Every 4 months if you rely mainly on tanker water.
- Every 3 to 6 months for restaurants, schools, clinics, mosques and other places where the public uses the water.
- Before summer and after the monsoon are the two best times of year.
- Immediately after sewage or floodwater enters the tank, or when the warning signs below appear.
The reasoning is in how often you should clean your water tank in Karachi.
Recognising Warning Signs That Your Tank Needs Immediate Cleaning
- Yellow, brown or cloudy water
- A sewage, rotten-egg or musty smell
- Slippery walls inside the tank
- Green or black growth on the walls
- Sediment, insects or larvae in the water
- Stomach illness that keeps returning, or several people ill at once
- Floodwater around or in the underground tank
A fuller list is in signs your family may be drinking contaminated water.
When to see a doctor
- Fever lasting more than three days
- Diarrhoea with blood, or lasting more than two days in a child
- Signs of dehydration: very little urine, dry mouth, sunken eyes, a drowsy or floppy child
- Yellow eyes or skin, or dark urine
- Severe headache with fever and a stiff neck. This is an emergency.
- Any diarrhoea or fever in a pregnant woman, a baby, or an elderly or chronically ill person
Start oral rehydration solution (ORS) straight away for diarrhoea while you arrange to see a doctor.
The Cost of Ignoring Tank Cleaning: A Karachi Perspective
One episode of typhoid or hepatitis means doctor’s fees, tests, medicines, possibly a hospital stay, and one or two weeks off work or school, often for more than one member of the household. Drug-resistant typhoid needs stronger, more expensive antibiotics than it did a decade ago.
Against that, cleaning both tanks of a typical house costs between Rs 2,500 and Rs 10,500 depending on size, twice a year. The table is on our charges page. The wider case is set out in the dangers of neglecting tank cleaning and the benefits of regular cleaning. For hygiene habits that support a clean tank, see the importance of tank cleaning for health and hygiene.
What to Look for in a Professional Tank Cleaning Service in Karachi
- Physical scrubbing or pressure washing of every surface, not just draining and rinsing
- Sludge removed by vacuum or pump
- A named, drinking-water-safe disinfectant at a measured strength
- Proper disposal of the waste, off your porch and roof
- Staff with protective gear, and a person stationed outside during underground work
- A registered company and a fixed rate with nothing added afterwards
- Inspection by you before payment, and a free re-clean if the work is not right
That is how we work. Our service guarantee and safety page give the details, and the reasons for each item are in why hire a professional tank cleaning company.
Frequently Asked Questions
Which waterborne disease is most common in Karachi?
Diarrhoeal infections are the most frequent. Typhoid and hepatitis A and E are the most common serious ones.
Can a dirty water tank cause typhoid?
Typhoid comes from sewage-contaminated water or food. A dirty tank does not create the bacteria, but it stores them, protects them from chlorine and keeps exposing the household.
Is boiled water safe if my tank is dirty?
Boiled water is safe to drink. The tank still exposes you through washing dishes and vegetables, brushing teeth, bathing and ablution.
Can I catch Naegleria from drinking tank water?
No. It infects only through the nose. Keeping tanks clean and chlorinated and avoiding water up the nose are the precautions.
Does tank cleaning prevent hepatitis?
It reduces the chance that hepatitis A or E virus delivered in one supply stays in your storage. Safe drinking water and handwashing remain essential.
Final Word: Clean Tanks, Healthy Families
These diseases are preventable. The city’s pipes are outside a family’s control. The tank on the roof and the tank under the porch are not. If you do not know when yours were last cleaned, call or WhatsApp 0313-2796778. We work across Karachi, including Orangi Town, Baldia Town and Shah Faisal Town.
About the author: Ahmar Shoaib is the founder of Karachi Tank Cleaning. He holds a BS in Chemical Engineering from Karachi University and has run the company’s cleaning and disinfection work since 2007. This article follows our editorial policy.
Sources: WHO Disease Outbreak News on typhoid (December 2018) and cholera (June 2022) in Pakistan; WHO fact sheet on hepatitis E; UNICEF Pakistan, WASH programme page; CDC pages on Naegleria fowleri and Cryptosporidium; PCRWR testing (2017), reported by Dialogue Earth; PCRWR and Sindh MICS figures reported by Geo News (May 2025); Dawn (January 2023 and June 2025); ARY News (July 2026).
