Universal Guide
How to Replace RO Water Purifier Filters
By Bikram Nath · Updated April 2026 · How we pick
Quick Answer
Replacing RO water purifier filters at home takes about 59 minutes. Turn off the inlet valve, drain residual pressure, unscrew the cartridges, insert new ones in the correct order (sediment → pre-carbon → RO membrane → post-carbon/UV), flush the first two tanks, then reset the indicator.
Every RO water purifier sold in India uses the same three- or four-stage filtration architecture. The brand, housing colour, and indicator electronics differ; the cartridge order and replacement procedure do not. This page documents the universal steps — if your specific model has unusual access (top-loading housings, screw-in-place cartridges), check the manual for the mechanical detail only.
The procedure — 6 steps, ~59 minutes
- 1
Turn off the inlet water supply
About 2 min
Locate the quarter-turn valve on the pipe feeding your RO unit (usually behind or under the purifier) and close it. If your installation has no dedicated valve, shut off the main kitchen supply. This prevents pressurised water spraying out when you open the housings.
- 2
Relieve pressure and drain stored water
About 1 min
Open the RO tap on the unit and let it run until the flow stops — usually 20–40 seconds as the storage tank empties. This removes residual pressure from the filter housings so cartridges come out cleanly.
- 3
Unscrew the cartridge housings
About 5 min
Most modern RO units have three to four cartridges arranged left-to-right: sediment, pre-carbon, RO membrane, and post-carbon (sometimes with UV after). Rotate each housing anticlockwise to release. Tool-free on Kent and Aquaguard; Livpure and Pureit units may need the bundled housing wrench. Catch residual water with a towel.
- 4
Insert new cartridges in the correct order
About 5 min
Order matters: sediment first (catches particles), then pre-carbon (removes chlorine), then RO membrane (removes dissolved salts), then post-carbon or UV (final polish). Push each cartridge fully into its housing — you should feel a slight resistance, then a seat. Do not force.
- 5
Restore water supply and flush the first two tanks
About 45 min
Re-open the inlet valve and wait for the tank to fill (typically 15–30 minutes). Drain the entire first tank by running the RO tap — this flushes manufacturing residue from new cartridges. Refill and drain a second time. Water from the third fill onwards is safe to drink.
- 6
Reset the filter-change indicator (if your model has one)
About 1 min
On units with an indicator (AO Smith, Kent Superb, Havells Digitouch), hold the reset button for 5–10 seconds until the service LED goes off or the display resets. Units without an indicator — write the replacement date on a sticker inside the cabinet for your next service.
When to call a technician instead
- Water tastes or smells noticeably different after three full tank flushes — the cartridges may be faulty or installed out of order.
- A housing won't seal and leaks after snug installation — the O-ring has failed; order a replacement before using.
- Your unit is a sealed tankless model (certain Aquasure and Livpure Pep Ultra variants) — these require brand technician access.
- The RO membrane change is more than 12 months overdue — brands void AMC coverage if membrane TDS rises past spec.
Related guides
- How often should you change RO filters?
- Best RO filter replacement kits in India
- Browse all Water Purifier guides