Your water tank needs cleaning if the tap water looks yellow or cloudy, smells musty or like sulphur, tastes metallic or flat, or if you can see algae or slime on the tank walls and lid. If you’ve noticed two or more of these, or it has been about six months since the last clean, don’t wait for the next scheduled service.<\/p>\n\n\n\n
Most people in Karachi only think about their tank when something goes wrong, and by then it has usually been overdue for months. A dirty tank almost always gives warning signs first, and checking for them yourself matters if you rely on water tank cleaning<\/a> only once or twice a year. This checklist runs from the obvious signs to the easy-to-miss ones, for both overhead and underground tanks.<\/p>\n\n\n\n Clean tank water should be clear with no tint. Water that looks pale yellow, brownish or slightly cloudy usually points to rust from an ageing tank or fittings, sediment stirred up from the tank floor, or organic matter breaking down inside.<\/p>\n\n\n\n Hold a glass of tap water up to the light. Specks of grit, tiny flakes or a fine film on the surface mean sediment has built up at the bottom of the tank and is being drawn into your supply line. This is common in older Karachi homes where the tank hasn’t been drained and scrubbed in a year or more.<\/p>\n\n\n\n A well-maintained tank gives water with little or no smell. Treat any of these as a clear signal:<\/p>\n\n\n\n If you also have pests around the tank area, deal with both together. Cockroaches and rodents are drawn to damp, undisturbed spaces like tank rooms and rooftop tank stands, and our cockroach control<\/a> and rats and rodent control<\/a> teams are often called to the same buildings that need tank cleaning.<\/p>\n\n\n\n If drinking water suddenly tastes metallic, flat or faintly bitter, and nothing else has changed (no new filter, no change in city water supply timing), the tank is the most likely cause. Taste is often the first thing residents notice, well before smell or colour.<\/p>\n\n\n\n This is the sign nobody wants, but it matters most. Contaminated stored water can cause stomach illness, so if more than one person at home has had unexplained stomach upset, diarrhoea or skin irritation after bathing, get the tank checked as one possible cause. Many things can cause these symptoms, so see a doctor if they persist. Our post on the health risks of dirty water tanks in Karachi<\/a> covers what contamination can lead to.<\/p>\n\n\n\n Sediment, biofilm and microbial growth build up gradually and invisibly, long before they produce a smell or a symptom, so time alone is a reason to clean. Given Karachi’s heat for most of the year and its humid monsoon stretch, we recommend cleaning overhead tanks roughly every six months. Underground tanks and heavily used building tanks may need it sooner. The reasoning is in our guide on how often to clean your water tank in Karachi<\/a>.<\/p>\n\n\n\n The first signs differ by tank type. For the cleaning differences in practice, see underground vs overhead water tank cleaning in Karachi<\/a>.<\/p>\n\n\n\n1. Look at the Water Itself<\/h2>\n\n\n\n
Colour and clarity<\/h3>\n\n\n\n
Visible particles<\/h3>\n\n\n\n
2. Smell Before You Use It<\/h2>\n\n\n\n
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3. Taste Changes<\/h2>\n\n\n\n
4. Physical Signs on the Tank Itself<\/h2>\n\n\n\n
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5. Health Symptoms in the Household<\/h2>\n\n\n\n
6. It’s Simply Been Too Long<\/h2>\n\n\n\n
Underground vs Overhead: Different Tanks, Different Warning Signs<\/h2>\n\n\n\n