Water safety in Karachi is hard to judge by eye. The most dangerous contamination has no colour, smell or taste, and the signs people do notice often appear only after a problem has been building for months. Still, there are patterns worth knowing, both in the water and in the household’s health.<\/p>\n\n\n\n
Below are ten warning signs, what each usually points to, and what to do about it. None of them is a diagnosis. Illness needs a doctor, and only a laboratory can confirm what is in the water.<\/p>\n\n\n\n
Karachi gets a little over half the water it needs, and it arrives for a few hours at a time through an ageing network. Every home stores it, usually in an underground tank and again on the roof. Testing has found most samples unsafe: in the 2017 round carried out for the Supreme Court’s commission, 107 of 118 Karachi samples failed<\/a>. How the water gets that way is covered in our guide to KWSB water supply<\/a>. The tank is where everything it carries comes to rest.<\/p>\n\n\n\n One bad meal explains one illness. Repeated cramps, nausea or loose motions in the same household, with no obvious food link, point to something everyone shares, and water is the most common shared exposure.<\/p>\n\n\n\n When two or more family members fall ill together, look for a common source. In a block of flats, ask the neighbours. If other households are affected, the shared tank is a prime suspect.<\/p>\n\n\n\n These spread by the faecal-oral route, often through water. A confirmed case in the house is a reason to boil all drinking water and clean both tanks immediately. Our article on typhoid, E. coli and the water tank link<\/a> explains the route.<\/p>\n\n\n\n Brown or yellow usually means rust and silt, often after a line repair or a long gap in supply. Green suggests algae, which needs light, so check the lid. Milky water that clears from the bottom up is usually just air.<\/p>\n\n\n\n Earthy or musty smells point to algae and organic growth. A rotten-egg smell means decay without oxygen, typically in deep sludge. A sewage smell is an emergency: stop drinking the water and have the underground tank inspected for seepage.<\/p>\n\n\n\n Metallic tastes come from rust and old pipes, salty or bitter tastes from borehole or tanker water, and a strong chlorine taste from recent dosing. Any sudden change is worth investigating.<\/p>\n\n\n\n Skin and eye irritation that appears after showers and eases when you are away from home can be caused by bacterial growth in stored water, though hard water and soaps are also common culprits.<\/p>\n\n\n\n Run a finger along the inside wall near the waterline. A slippery film is biofilm. A dark layer on the floor is sludge. Wriggling larvae mean mosquitoes are breeding, and the WHO’s advice for dengue control is to keep water storage containers covered and cleaned<\/a>.<\/p>\n\n\n\n If cartridges that should last months turn brown in weeks, the tank is feeding them sediment. This is covered in water filter versus tank cleaning<\/a>.<\/p>\n\n\n\n The Sindh health department’s minimum is once a year before summer<\/a>. If it has been longer than six months, or the date is unknown, treat the tank as overdue.<\/p>\n\n\n\nTen warning signs<\/h2>\n\n\n\n
1. Stomach upsets that keep coming back<\/h3>\n\n\n\n
2. Several people ill in the same week<\/h3>\n\n\n\n
3. A diagnosis of typhoid or hepatitis A or E<\/h3>\n\n\n\n
4. Cloudy or coloured water<\/h3>\n\n\n\n
5. A smell<\/h3>\n\n\n\n
6. An odd taste<\/h3>\n\n\n\n
7. Rashes or sore eyes after bathing<\/h3>\n\n\n\n
8. Slime, sediment or insects in the tank<\/h3>\n\n\n\n
9. Filters clogging quickly<\/h3>\n\n\n\n
10. Nobody remembers the last cleaning<\/h3>\n\n\n\n
Read the signs: a quick reference<\/h2>\n\n\n\n