Most Dhaka buildings store water twice — in an underground reservoir and in one or more rooftop tanks. That water is used for bathing, washing and often cooking, but the tanks themselves are rarely checked. Sediment, sludge and algae build up quietly until the water looks cloudy or smells.
How often?
For most residential buildings, cleaning the rooftop tanks and underground reservoir every six months is a sensible routine. Clean immediately if you notice any of the warning signs below, after flooding, after construction work nearby, or before moving into a building whose tank history you do not know.
Warning signs
- Cloudy, yellowish or brown water
- Particles or sediment in buckets
- A musty or unpleasant smell
- Slimy feel on the inside of taps and shower heads
- Frequently blocked tap filters
- Insects or larvae visible when the lid is opened
What a proper tank clean involves
- Residents are informed and water is stored for the cleaning period.
- Pumps are switched off and the tank is drained.
- The tank is ventilated before anyone enters, and a team member stays outside the tank throughout.
- Sludge and sediment are removed.
- Walls, floor and ceiling are scrubbed and pressure washed.
- The tank is disinfected with a measured chlorine solution.
- It is rinsed thoroughly before refilling.
Why safety matters
Tanks and reservoirs are confined spaces. Poor air, slippery surfaces and electrical pumps make them dangerous for untrained workers. A proper team switches off pumps, ventilates the tank and never works alone inside it.
Keep it clean longer
- Keep tank lids closed and in good condition.
- Repair cracks in reservoir covers so rainwater and insects cannot enter.
- Check for leaks around the pump and pipes.
Water tank cleaning with Safai Bangladesh starts from ৳2,500 per tank, and building committees can book all tanks and the reservoir in one visit.