The RO membrane is the expensive consumable in a water purifier, which makes it the part most often recommended and the part least often actually failed.
The good news is that unlike almost every other component in a home, this one can be tested in two minutes with a device that costs very little. A TDS meter gives you a number before and after the purifier. If the output number is low, the membrane is working — whatever else is wrong with the unit.
That single test is why this page exists. Slow flow, odd taste and low output all get attributed to the membrane, and most of the time the honest answer is a choked pre-filter costing a fraction as much.
A note on these numbers. XpertWorker is a marketplace, not a service company. We do not set any professional's price and we never charge you a paisa. Every figure below is an indicative market range collected from what independent professionals in Delhi NCR generally charge — a guide to help you judge a quote, not a quote itself.
In this guide
RO parts and labour — Delhi NCR, 2026
Look at the gap between the first row and the second. That gap is the reason to test before agreeing.
| Job | Typical market range | What it usually includes |
|---|---|---|
| RO membrane replacement | ₹1,200–2,500 | Membrane plus fitting |
| Sediment / carbon filter (per filter) | ₹250–600 | The cheap parts that protect the expensive one |
| Water / TDS testing | ₹100–300 | Settles the membrane question outright |
| UV lamp replacement | ₹500–1,200 | Different job, often quoted alongside |
| Pump / SMPS / adaptor replacement | ₹600–1,800 | The other cause of weak or no output |
Indicative Delhi NCR market ranges, 2026. Each professional sets their own charge and quotes you free before starting. Parts are normally billed on top of labour.
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Get free quotesThe TDS test — how to settle it yourself
TDS is total dissolved solids, measured in ppm. The membrane's entire job is to reduce it. So measuring it tells you directly whether the membrane is doing its job.
- Take two readings. One from the tap that feeds the purifier (the input), one from the purifier's own outlet (the output).
- A healthy membrane makes a large difference between them. A working domestic RO typically brings the number down substantially — the exact figures depend on your supply and the unit, which is why the gap matters more than either number alone.
- Output close to input means the membrane is not filtering. That is the case where replacement is genuinely indicated.
- Output still low means the membrane is fine. If your complaint is slow flow or taste, look at the pre-filters, the pump or the storage tank instead.
- Write both numbers down with the date. One reading is a snapshot; a series is evidence, and it tells you a membrane is drifting months before it fails.
What your symptom usually means
- Slow flow, purifier otherwise fine. Almost always a choked sediment or carbon pre-filter. Delhi's supply carries enough sediment that these clog well ahead of schedule. Cheapest possible fix, checked first.
- No water at all. Look at power, the SMPS or adaptor, and the pump before the membrane. A dead pump produces no water regardless of membrane condition.
- Water tastes different, TDS output has risen. This is the genuine membrane case.
- Water tastes stale but TDS is fine. The storage tank, not the membrane. Ask for it to be sanitised.
- Purifier runs constantly or keeps restarting. Usually the float valve or the pressure switch — a small part, not a membrane.
- Too much reject water. Some reject is normal and by design. A sudden increase can point to a membrane at the end of its life, but check the flow restrictor first.
Our RO not working guide walks the full diagnostic, and the repair cost guide covers every part.
How long a membrane lasts, and what GPD means
- A few years is normal for a domestic membrane where the pre-filters have been changed on time. Where they have not, it can be a fraction of that — the pre-filters exist to protect the membrane, and neglecting them is the single commonest reason a membrane dies early.
- High input TDS shortens membrane life. Parts of Delhi NCR run hard, silty supply, and a membrane there works harder for the same output.
- GPD is gallons per day — the membrane's throughput rating, commonly 75, 80 or 100 for domestic units. A higher GPD fills the tank faster; it does not filter better. Fit the rating your unit is designed for rather than assuming higher is an upgrade, because the pump and flow restrictor are matched to it.
- Membranes are also rated for a TDS ceiling. If your supply is high-TDS, that matters when choosing — tell whoever is supplying it what your input reading is.
- Ask to see the packaging and keep the box. It is your record of what was actually fitted, and prices for the same nominal item vary enormously.
- Change the pre-filters at the same time. Fitting a new membrane behind old, choked pre-filters is starting its life at a disadvantage.
Our filter change guide covers the schedule, and the AMC guide covers whether a contract makes this cheaper.
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Get free quotes →Frequently asked questions
How much does RO membrane replacement cost in Delhi?
How do I know if my RO membrane needs replacing?
How long does an RO membrane last?
Is slow water flow a sign of a failed RO membrane?
What does GPD mean on an RO membrane?
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How we put this guide together
The ranges in this guide are indicative market rates compiled from real jobs across Delhi NCR and reviewed by the XpertWorker pricing desk. They are not quotes, and they are not our prices — every independent, local professional sets their own charge and quotes you free before any work starts.