Free tool

TDS Calculator: Which Water Purifier Do You Actually Need?

Which purifier do you actually need?

Enter your water's TDS. If you do not know it, a digital TDS meter costs about ₹300 and is the single most useful thing you can buy before a purifier.

Your water TDS: 450 ppm

20500 (BIS limit)2500

Your water source

My area has known arsenic, fluoride, nitrate or heavy-metal issues

Recommendation

You need RO, with a TDS controller

Buy: RO + UV + UF with TDS controller · Typical spend ₹15,000 - ₹20,000

At 450 ppm you are above the level where UV alone is adequate.
A standard RO rated to 2,000 ppm input covers this comfortably.
The TDS controller matters: without it, output tastes flat and you cannot adapt to seasonal changes.

See best RO + UV + UF purifiers

This calculator exists because the single most consequential decision in buying a water purifier gets skipped almost universally: measuring your water. A ₹300 TDS meter tells you whether you need a ₹2,800 gravity purifier or a ₹34,000 brackish-water RO, and getting it wrong in either direction is expensive.

Over-buying is the more common error. A large number of Indian households run RO purifiers on treated municipal supply below 200 ppm, paying more upfront, more in running costs, discarding thousands of litres a year, and stripping out calcium and magnesium — all to solve a problem that was not there. If your reading comes back low, take the win.

Under-buying is rarer but more serious. A UV purifier on borewell water in a fluoride or arsenic belt looks and feels like protection while providing none against the contaminant that actually matters. If you are in West Bengal, Bihar, Assam, eastern UP, Rajasthan or Punjab, get a laboratory test, not just a TDS reading.

Frequently asked questions

How do I measure my water's TDS?

Buy a digital TDS meter — around ₹300 online. Fill a clean glass with tap water, let it settle for a minute, and dip the meter to the marked depth. Test at different times of year if your supply blends municipal and borewell water, because seasonal swings of 300-500 ppm are normal. Test your purifier's output too, so you can verify it is working.

What TDS is safe for drinking water in India?

BIS IS 10500 sets 500 ppm as the acceptable limit and 2,000 ppm as the permissible maximum where no alternative source exists. For taste and mineral content, 50-150 ppm is ideal — which is what you should target as your purifier's output using a TDS controller.

Can a TDS meter tell me if my water is safe?

No, and this is the most important limitation to understand. TDS measures total dissolved solids as a single number; it cannot distinguish harmless calcium from dangerous arsenic. Water at 120 ppm could contain arsenic and read as excellent. Use TDS to choose your technology, and a NABL-accredited laboratory test to establish whether your water is safe.

Not sure what you actually need? Ask us before you spend.

Tell us your city, your water source and your budget. For homes we will recommend the right technology — including telling you when a ₹3,000 purifier is genuinely enough. For offices, societies and factories, our team will size a system against your water report and send a specification-backed quotation.

Or email betterworkindia@gmail.com — attach a water analysis report and we can quote faster.