Water purifier diagnostics
Your RO purifier is leaking — find the source before anything else
Most domestic RO leaks come from a filter-housing O-ring that was not seated properly at the last service, or from a push-fit connector that was disturbed. Both are cheap. A cracked housing or a failed tank is not.
Important
Before you open anything
- Unplug at the socket and close the inlet before touching anything. A leak inside the cabinet can energise the casing.
- Release system pressure by opening the purified-water faucet before undoing any housing. These systems hold pressure after shutdown.
- Never over-tighten a filter housing to stop a leak. Over-tightening is what cracks them, and a cracked pressure housing can fail suddenly.
Does this match your symptoms?
- Water pooling under or behind the unit
- Damp patch on the wall below a wall-mounted purifier
- Dripping that starts only when the machine runs
- Constant slow seep even when the unit is idle
Work through the causes in this order
Ordered by how often each turns out to be the real cause — not by what it costs to fix.
- Most commonYou can fix this₹20 – ₹150
1. Filter housing O-ring not seated
How to confirm it
Leaks that begin within days of a filter change are almost always this. Look for water tracking down from the seam between a housing bowl and its cap. The O-ring may be twisted, pinched, dirty or simply missing.
The fix
Depressurise, unscrew the housing, clean the groove, seat the O-ring flat and lightly lubricate it with food-grade silicone grease. Retighten firmly by hand with the spanner — not with force, which is what cracks housings.
Part: Housing O-ring
- Most commonYou can fix thisUp to ₹250
2. Loose or badly fitted push-fit connector
How to confirm it
Dry everything thoroughly, run the unit, and watch each connector. Push-fit fittings leak when the tube end was cut at an angle, scored, or not pushed fully into the collet.
The fix
Depressurise, release the collet, cut the tube end square with a proper tube cutter, and push it fully home until it seats. If the O-ring inside the fitting is damaged, replace the fitting.
Part: Push-fit connector, if damaged
- CommonTechnician job₹300 – ₹900
3. Cracked filter housing
How to confirm it
Look for a hairline crack, usually radiating from the threaded neck. Over-tightening at a previous service is the usual cause. The leak typically worsens as pressure rises.
The fix
Replace the housing. Do not attempt to seal a cracked pressure housing — it is under continuous pressure and adhesive repairs fail without warning.
Part: Filter housing
- OccasionalTechnician job₹800 – ₹1,800
4. Failed storage tank
How to confirm it
A tank leak produces a steady seep that does not depend on whether the machine is running, and the water appears at the tank rather than at the filter bank. On pressurised tanks a failed bladder can also weep from the air valve.
The fix
Replace the tank. Tanks are not economically repairable.
Part: Storage tank
- OccasionalYou can fix this₹150 – ₹700
5. Faucet or diverter seal
How to confirm it
Water appearing on the countertop around the dispensing faucet rather than inside the cabinet points at the faucet seal or its mounting washer.
The fix
Replace the faucet washer or the faucet assembly.
Part: Faucet washer or assembly
When to stop and call a technician
- You cannot locate the source after drying and observing the unit
- The leak is anywhere near the SMPS, pump or wiring — treat this as electrical, not plumbing
- A housing is cracked, or the tank is seeping
- The unit is wall-mounted and water is tracking inside the wall
Costs shown are indicative bands for India, published so you can sanity-check a quote — they are not quotations, and they vary by brand, city and whether the technician is brand-authorised. Last reviewed 2026-08-08.