7 Signs Your Water Tank Needs Cleaning Urgently

Tanks rarely fail suddenly. They degrade, and they signal it. Here are the seven signs in roughly the order they show up.

1. The water smells

Musty means biofilm. Eggy means anaerobic sediment and sulphate-reducing bacteria. Either way, smell is the earliest reliable warning and the one people most often decide to live with.

2. Sediment in the bucket or the aerators

Grit at the bottom of a filled bucket, or gritty residue when you unscrew a tap aerator, means the sediment layer has risen past the tank outlet and is travelling through your plumbing.

3. Yellow or cloudy water in the evening

Specifically in the evening, after a day of use has drawn the tank down to its sludge line. Clear in the morning, discoloured at night is a textbook sediment signature.

4. Falling pressure

Gradual pressure loss across every tap usually means either the outlet is partially occluded by silt or the pipe run has scaled. Both are worth checking before anyone suggests a new pump.

5. Slippery walls or a green tint

If you can see into the tank and the walls feel slippery or look tinted, that is established biofilm and algae. It will not rinse off and it is regrowing continuously.

6. Anything alive

Larvae, worms or insects mean something has an entry route — almost always a cracked lid or an unmeshed overflow. Stop drinking the water, get it cleaned, and close the route. Cleaning without closing the route buys you one season.

7. Recurring stomach upsets in the household

The one people connect last. If more than one person in the house has had unexplained gastric trouble and nothing in the kitchen explains it, the tank is worth ruling out. It is a cheap thing to eliminate from the list.

The signal that is not a signal

Clear water is not evidence of a clean tank. Sediment settles, biofilm clings to walls rather than floating, and most bacterial contamination is invisible. A tank that looks fine from a tap can still be well past its interval — which is exactly why the interval exists.

When did you last clean it?

If the honest answer is "I am not sure", it has been too long. Six months for DJB-fed home tanks, four for borewell or tanker supply, four in hard-water areas.