Quick answer
An RO service visit typically includes: checking input and output TDS, inspecting and replacing pre-filters as due, checking membrane performance, checking the UV lamp and pump, sanitising the tank, and inspecting all fittings for leaks. Pre-filters are commonly changed every 3–6 months, carbon filters every 6–12 months and the membrane every 1–2 years — but input water quality and usage change this a lot.
Typical filter replacement schedule
These are common trade intervals for domestic RO purifiers. Follow the manufacturer's recommendation for each model, and shorten intervals for borewell or high-TDS water.
| Component | Typical interval | Notes |
|---|---|---|
| Sediment pre-filter | Every 3–6 months | Visible discolouration means it is due. Muddy or tanker water can choke it sooner. |
| Pre-carbon filter | Every 6–12 months | Protects the membrane from chlorine in municipal water. |
| RO membrane | Every 1–2 years | Replace based on output TDS and flow, not only the calendar. |
| Post-carbon filter | Every 6–12 months | Affects taste and smell of the output water. |
| UV lamp | About yearly, or as per manual | A lit lamp can still be weak; follow the rated life. |
| UF membrane (if fitted) | Every 1–2 years | Check flow and cleanliness. |
Service visit checklist
| Task | Frequency | Notes |
|---|---|---|
| Measure input TDS | Every visit | Record it. Changes in source water explain many complaints. |
| Measure output TDS | Every visit | A steady rise usually points to membrane wear. |
| Check output flow rate | Every visit | Low flow: choked pre-filter, membrane or weak pump. |
| Inspect sediment and carbon filters | Every visit | Replace if due or visibly dirty. |
| Check booster pump and pressure | Every visit | Noise, heating, or pump running continuously. |
| Check high-pressure and low-pressure switches | Every visit | Faulty switches cause overflow or the unit not stopping. |
| Check SV (solenoid valve) and float | Every visit | Common cause of continuous drain flow. |
| Clean and sanitise storage tank | Every service or as per manual | Use a food-grade sanitiser and rinse thoroughly. |
| Inspect pipes and fittings for leaks | Every visit | Tighten or replace push fittings showing seepage. |
| Check UV lamp and adapter | Every visit | Lamp on, no flicker, adapter not overheating. |
| Check reject water ratio | Twice a year | Adjust flow restrictor if set wrongly. |
Adjusting for the water source
- Municipal supply: chlorine is the main concern; the carbon filter protects the membrane. Intervals usually follow the standard schedule.
- Borewell water: higher TDS and hardness shorten membrane and pre-filter life. Note the input TDS on the first visit.
- Tanker or mixed supply: water quality changes month to month. Shorten pre-filter intervals and record TDS every time.
Recording input TDS on each visit gives you a clear reason to explain to the customer why their filters wear out faster than a neighbour's.
Signs the membrane needs replacing
- Output TDS has risen noticeably from the reading after installation
- Output flow is low even after new pre-filters
- Taste has changed and does not improve after carbon filter replacement
- The membrane has passed its typical life for that water source
Common RO complaints and likely causes
| Complaint | Likely causes | First check |
|---|---|---|
| Low or no water output | Choked pre-filter, worn membrane, weak pump, low inlet pressure | Check filters first, then pump pressure. |
| Water keeps draining | Faulty solenoid valve or float, high-pressure switch | Common and quick to fix. |
| Bad taste or smell | Exhausted carbon filters, dirty tank | Replace carbon, sanitise the tank. |
| High output TDS | Membrane wear, change in source water | Compare with input TDS before replacing. |
| Leakage under the unit | Loose push fittings, cracked filter housing | Replace fittings rather than taping them. |
| Unit makes noise | Pump wear, air in the line | Check pump mounting and inlet. |
Commercial RO plants
Plants for offices, schools and clinics run longer hours. In addition to the domestic checklist, technicians commonly check multiport valves, pressure gauges, dosing systems (if fitted) and media filters. Service frequency is usually monthly or as per the plant's manual.
Writing filter changes into the AMC
Decide up front whether filters are included. Many RO AMCs include pre-filters but charge the membrane separately — see comprehensive vs non-comprehensive AMC for how to frame it.
RO businesses can see how contracts and complaints work on our RO service management software page. More on AMC software and our AMC management software.
How AMCFlow helps
- Add each purifier or plant as a unit under the customer, with its AMC start and end dates.
- Customers can log in to the customer portal with WhatsApp OTP and raise a complaint when the water tastes off or flow drops.
- Each complaint gets a number and can be assigned to a technician, who receives a WhatsApp job alert with customer, mobile, address, product, problem and complaint number.
- Expiry dashboard shows RO contracts nearing expiry.
Frequently asked questions
How often should RO filters be changed?
Sediment pre-filters are commonly changed every 3 to 6 months, carbon filters every 6 to 12 months and the membrane every 1 to 2 years. Water quality and usage can shorten these intervals.
How do I know if an RO membrane needs replacement?
Common signs are rising output TDS, low output flow even with new pre-filters, and a change in taste. Compare readings with earlier visits.
Does borewell water affect RO maintenance?
Yes. Borewell water often has higher TDS and hardness, which shortens the life of the membrane and pre-filters. Record input TDS on each visit.
What is checked during an RO service?
Input and output TDS, flow rate, pre-filters, pump, pressure switches, solenoid valve, UV lamp, storage tank hygiene and all fittings for leaks.
Is the RO membrane included in an AMC?
It depends on the contract. Many RO AMCs include pre-filters but charge the membrane separately. The contract should state this clearly.