Water that sits in a tank for months, exposed to heat, dust and whatever the supply pipe carries in, is the same water used for bathing, washing vegetables and sometimes cooking. Most households have no real sense of when their tank was last cleaned, if ever. The right frequency depends mostly on where your water comes from.
Frequency by water source
- Delhi Jal Board (municipal) supply: roughly every 6 months is a sensible routine. Municipal water is treated before it reaches your tank, so sediment builds up more slowly, but algae and a slimy biofilm still form over time, especially in summer heat.
- Borewell supply: every 3 to 6 months. Groundwater carries more dissolved minerals and fine sediment than treated municipal supply, so tanks fed by a borewell tend to collect sludge faster.
- Tanker-fed supply: closer to every 3 months. Tanker water quality varies a lot between suppliers and trips, and it often carries more silt than piped supply, which settles at the bottom of the tank faster than either of the other two sources.
If your home uses a mix, for example a borewell as backup during water cuts, lean toward the shorter interval.
Signs your tank is already overdue
Even on a regular schedule, watch for these signs that cleaning should happen sooner:
- A smell from the tap, especially noticeable first thing in the morning
- Sediment settling at the bottom of a glass or bucket after the water stands for a few minutes
- Visible green or brown algae on the inside walls when the lid is opened
- A slimy feel on the inside of pipes or at the tap aerator
- It has been more than 6 months since the last clean, or you genuinely do not know when it last happened
The 9-step cleaning process
A proper tank clean is not a quick rinse. It follows a set sequence to make sure sediment, algae and biofilm are actually removed rather than just stirred up and left to resettle.
- Inspect the tank, lid, inlet and outlet pipes, and note the condition before starting.
- Drain the tank fully.
- Remove sludge that has settled at the base, usually the thickest and most stubborn layer.
- High-pressure wash of the walls and floor to loosen remaining buildup.
- Hand scrub the walls, corners and lid, since pressure alone does not remove algae stuck to the surface.
- Vacuum extraction of the loosened dirt and water, so it does not get redeposited while draining.
- Disinfect the inside surfaces.
- Rinse thoroughly with fresh water to clear any residue.
- Before and after photos, sent on WhatsApp, so you have a record of the work done.
This sequence applies to both overhead tanks and underground sumps, though the equipment and time needed differ between the two.
Overhead tanks vs underground sumps
| Tank | Capacity | Price (incl. GST) |
|---|---|---|
| Overhead | Up to 1,000 L | ₹699 |
| Overhead | 1,001-2,000 L | ₹999 |
| Overhead | 2,001-5,000 L | ₹1,499 |
| Underground sump | Up to 1,500 L | ₹1,199 |
| Underground sump | 1,501-3,000 L | ₹1,499 |
| Underground sump | 3,001-5,000 L | ₹1,999 |
| Underground sump | 5,001-10,000 L | ₹2,799 |
| Underground sump | 10,001-15,000 L | ₹3,299 |
| Underground sump | 15,001-20,000 L | ₹3,799 |
| Underground sump | 20,001-30,000 L | ₹4,499 |
| Above 30,000 L | Society / commercial | Free visit, then fixed quote |
Swipe to see all home sizes
₹200 off each extra tank cleaned on the same visit.
Overhead plastic tanks are generally quicker to access and clean, since they sit above ground with a lid that opens directly. Pricing is based on capacity, from up to 1,000 litres through to 5,000 litres, with tanks above that size quoted after a free visit.
Underground sumps take more time and effort. They are usually concrete, larger in capacity, and need the team to physically get inside to scrub walls and remove sludge, which is harder work than an overhead tank of the same size. That is reflected in sump pricing running a little higher than an overhead tank of similar capacity, with sump options available up to 30,000 litres before moving to a custom quote. Tanks or sumps above 30,000 litres, including society and commercial setups, get a free visit followed by a fixed quote.
If you have more than one tank, each additional tank cleaned on the same visit gets a discount off the per-tank price, since the team is already on site with equipment set up.
Before the team arrives
A few things make the visit faster:
- Store enough water for a few hours while the tank is being cleaned, since it will be empty during the process.
- Switch off the motor so it does not run dry or pump into an empty tank.
- Give clear access to the roof or sump area, including keys to any locked terrace door if applicable.
Keeping it clean between visits
A cleaning schedule works better alongside a few habits: keep the tank lid closed and check that it actually seals, make sure the overflow pipe has a mesh cover to stop debris and insects getting in, and avoid storing anything on top of the tank lid that could crack or weaken it over time. None of this replaces a proper clean on the schedule above, but it slows down how quickly sediment and algae build up in between.
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