RO water purifier maintenance: filters, membranes and service intervals
· 4 min read
Change an RO purifier's sediment pre-filter every 3 to 6 months, the carbon filter every 6 to 12 months, and the RO membrane every 1 to 2 years depending on how hard your water is. A UV lamp, if one is fitted, needs replacing about once a year, because it stops disinfecting long before it stops glowing.
An RO purifier keeps working invisibly until it doesn't — and by then you may have been drinking under-filtered water for weeks. The parts wear on a schedule, so it pays to track them.
The parts and their typical lifespan
Four consumables on four different schedules, which is precisely why people lose track of them. The sediment filter clogs first by design, because its whole job is protecting everything behind it.
- Sediment (pre) filter: every 3–6 months — it protects everything downstream and clogs first.
- Carbon filter: every 6–12 months — removes chlorine and odour.
- RO membrane: every 1–2 years depending on water hardness — the heart of the system.
- UV lamp (if fitted): about once a year — it stops disinfecting long before it stops glowing.
Signs something's due
Flow rate is the earliest honest signal, and the one to watch. Taste and smell change later, which means by the time the water tells you, it has been telling you for a while.
- Slower water flow or a smaller purified output than usual.
- A change in taste or a faint smell.
- The purified-water tank taking much longer to fill.
- The service-reminder or filter-change light, if your model has one.
Cost and the AMC question
Filters run roughly ₹300–₹800 each; a membrane ₹1,500–₹3,000. Because these recur predictably, a purifier AMC that bundles consumables is one of the few AMCs that reliably saves money over buying parts individually — as long as it actually includes the membrane.
Keep a note of what was changed and when, so the next technician (or the next you) isn't guessing whether the membrane is one year old or three.
Common questions
How often should RO filters be changed?
The sediment pre-filter every 3 to 6 months, the carbon filter every 6 to 12 months, and the RO membrane every 1 to 2 years. Harder water shortens all three. If your purifier has a UV lamp, plan on replacing it yearly regardless of whether it still lights up.
Why is my RO purifier's water flow slow?
Start with the sediment pre-filter, which is the usual answer and the cheapest to rule out. If that's recently changed, the next candidates are low input water pressure and a membrane approaching the end of its life. All three reduce output, so replacing parts at random is an expensive way to find out which.
What happens if you don't change the RO membrane?
Output drops and more dissolved solids get through, so you keep paying for a purifier that is quietly doing less purifying. A degraded membrane also sends a larger share of the water to the drain, so the running cost rises at the same time as the water quality falls.
Is an RO AMC worth it?
For purifiers specifically it usually is, because the consumables recur on a known schedule rather than arriving as surprises. One clause decides it: check the contract includes the RO membrane and not just the filters. A contract covering only filters is covering the cheap half.
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