Quick answer: Choose treatment from a water-quality test and the purifier’s verified contaminant-removal capability. A TDS reading on its own cannot establish whether water is safe to drink, or decide between RO, UV and UF.
Test your water before you shop
TDS describes dissolved solids, not every safety hazard. Arrange appropriate water testing and choose treatment for the contaminants found.
WHO guidance and BIS drinking water standards both treat TDS up to 500 ppm as acceptable, with 500 ppm as the desirable upper limit for Indian drinking water. That is why blanket “buy RO” advice is wrong for a lot of Indian households.
What each technology actually does
| RO | UV | UF | Activated carbon | |
|---|---|---|---|---|
| Removes dissolved salts | Yes | No | No | No |
| Microbial reduction — verify the complete system’s tested performance | Yes | Yes | Partly | No |
| Removes heavy metals (arsenic, lead) | Yes | No | No | No |
| Removes chlorine, odour, taste | Partly | No | No | Yes |
| Removes visible particles and cysts | Yes | No | Yes | No |
| Needs electricity | Yes | Yes | No | No |
| Wastes water | Yes, significant | No | No | No |
| Best for | High TDS, borewell, tanker | Bacteriologically unsafe but low TDS | Muddy or turbid water | Taste and smell |
Most sold units combine several stages, typically sediment filter, carbon filter, then RO or UF, then UV, then a mineraliser. The combination matters more than any single acronym.
The water wastage nobody mentions at the showroom
A standard domestic RO discharges roughly 2 to 3 litres of reject water for every 1 litre purified. On 10 litres of drinking water a day, that is 20 to 30 litres down the drain daily. Newer models advertise better recovery ratios, and some include a save-water feature that routes reject water to a storage tank for washing or mopping. If you live in a water-stressed city, this is worth prioritising, and it is also why running RO on already-soft municipal water is a bad trade.
What to check before buying
- Storage capacity: 6 to 8 litres suits a family of four. Larger helps if you have frequent power cuts.
- Rated TDS limit of the membrane. Buying a unit rated to 2,000 ppm for 1,500 ppm water is fine; the reverse is not.
- Annual maintenance cost, typically ₹2,000 to ₹4,000, which is the real cost of ownership. Filter changes are needed roughly yearly, RO membranes every 2 to 3 years.
- Service network in your city. A purifier without local service becomes a plastic box when the membrane fails.
- Whether a service plan is bundled for the first year or two, and what it excludes.
- Pump and pressure requirements. Low incoming pressure needs a booster pump; check before installation.
- Wall space and drain access, since RO units need a drain line for reject water.
Running costs
| Item | Frequency | Typical cost |
|---|---|---|
| Sediment and carbon filters | Every 6–12 months | ₹600–₹1,200 |
| RO membrane | Every 2–3 years | ₹1,500–₹3,000 |
| UV lamp | Every 12–18 months | ₹500–₹1,200 |
| Annual service visit | Yearly | ₹400–₹800 |
| Electricity | Continuous | Minimal, roughly 25–60 W while running |
Budget ₹2,500 to ₹4,000 a year for a typical RO+UV unit. Cheap purifiers with expensive proprietary filters often cost more over five years than a pricier unit with standard parts.
Common mistakes
- Buying RO for low-TDS municipal water, which removes useful minerals and wastes water for no benefit.
- Ignoring TDS entirely and buying on brand advertising.
- Skipping filter changes until the taste changes; by then the filter has been ineffective for months.
- Assuming RO handles muddy water. High turbidity clogs membranes fast; you need adequate pre-filtration.
- Forgetting the mineraliser on an RO unit, which adds back calcium and magnesium after purification.
Frequently asked questions
Is RO water bad for health?
RO removes dissolved minerals along with contaminants. For most people eating a normal diet this is not a health problem, but it does change taste and is unnecessary where water is already low in TDS. A mineraliser stage addresses it.
Do I need a purifier if I get municipal water?
Usually yes, but often not RO. Municipal supply can pick up contamination in old pipes and overhead tanks, so UV+UF gives protection without the wastage.
How often should I clean the storage tank?
Every three to six months. A clean purifier with a dirty tank still gives you contaminated water.
Is a gravity purifier enough?
For low-TDS, bacteriologically reasonable water with no power supply, a good gravity UF unit is a legitimate low-cost option. It will not handle high TDS or heavy metals.
Last updated September 2026. Prices and service costs vary by brand and city; verify current model specifications before buying. Get your water tested for an accurate recommendation. Some links on this site may be affiliate links, which do not affect what you pay.
About the prices in this guide. Indian retail prices move week to week and vary by seller, variant, city and festive offer, and no authority publishes them. Treat every figure here as indicative — useful for judging which tier a product sits in, not as a current quote. Check the live listing price, the exact variant and the final payable amount, including delivery and any exchange or bank offer conditions, before you buy.
Sources
Checked against: WHO — total dissolved solids in drinking water. Rules, fees and rates change — check the official page before you act on anything here.
Article Was Generated By AI.