After a water tank is cleaned, three kinds of waste are left: sludge from the floor, dirty wash water, and chlorinated rinse water. All three should go into a sewer drain, in a controlled way, and none of it onto the street, into a storm drain, onto a garden or into the ground beside the

Climate change affects Karachi’s water tanks in four ways. Hotter weather makes bacteria grow faster in stored water. Heavier monsoon bursts flood underground tanks and push sewage into supply lines. Longer shortages mean water sits in tanks for more days and more of it comes from tankers and bores. Rising seas make groundwater saltier, which

Eco-friendly water tank cleaning means removing dirt mechanically first, disinfecting with a product that breaks down into harmless substances, using the correct dose and no more, and disposing of the waste properly. The safest products for a drinking water tank are chlorine at the right strength, hydrogen peroxide or silver hydrogen peroxide, and food-grade citric

A rainwater harvesting system collects rain from your roof, filters it and stores it in a tank or sends it into the ground. In Karachi its main benefits are free water during the monsoon months, fewer tanker purchases, less flooding around the house, and soft water that leaves no scale. A 120 square yard roof

Rainwater harvesting and tank cleaning belong together. A roof in Karachi can collect thousands of litres in a single monsoon spell, but that water is only useful if the tank it goes into is clean, covered and separate from anything it could contaminate. Sustainable living in a water-short city comes down to three habits: catch