Water Tank Cleaning: Before and After

Most people never look inside their rooftop tank. The water from the tap looks clear, so the tank must be fine. These photos show why that isn't a safe assumption.

What the "before" photos show

Sludge on the floor. Fine silt in Delhi's municipal and borewell supply settles to the bottom of the tank. Over months it builds into a soft brown or black layer — in several of these tanks it covered the whole floor. Every time the water level drops low, that layer is stirred up and sent towards your taps.

Dark, cloudy water at the bottom. When we open a tank and lower the water, the last few inches are often grey or black. This is the water closest to the outlet.

Rust-coloured spots. Iron in the supply and corroding fittings leave orange-brown deposits, especially around the float valve and outlet.

None of this is unusual. It's what an overhead tank looks like after six to twelve months without cleaning.

What we did

Each tank went through our standard process: we drained it, removed the sludge by hand, scrubbed the floor and walls, vacuumed out the dirty water, disinfected the surfaces and rinsed. See the full water tank cleaning process for each step.

Underground tanks (sumps)

Underground tanks collect even more silt, because water rests there first. In tiled sumps like the one below, mud settles on the floor and stains build up in the tile joints.

What the "after" photos show

Clean ribbed walls, a clean floor with no sediment, and clear fittings. That's the standard we aim to leave every tank in — and we send you before and after photos of your own tank on WhatsApp so you can see it for yourself.

How often should you clean?

For most Delhi homes, every six months is sensible; sooner if you notice smell, cloudiness or silt in a bucket. Our guide on how to remove sludge from a water tank explains the warning signs.

What to look for in your own photos

Compare the tank floor (sludge gone?), the walls and corners (no green or black film?), the underside of the lid and the area around the inlet. These are the places dirt builds up first — and the places a quick rinse misses.