Do You Need a Water Purifier? An Honest Decision Guide for Indian Homes

Most Indian homes need some form of water treatment, but not always an RO purifier. If your water is low-TDS municipal supply, UV or UF (or boiling) handles the main risk, which is microbes. If it is high-TDS, borewell or tanker water, or a test shows fluoride, arsenic or nitrate above the limits, you need RO. Test before you buy.

The Short Answer by Situation

Your situation	What you likely need
Municipal water, TDS under about 200, tastes fine	UV or UF purifier, or boiling; RO is usually overkill
Municipal water, TDS about 200 to 500	UV or UF is often enough; RO is optional, mainly for taste
TDS above 500, any source	RO rated for your input TDS, with UV or UF
Borewell water	A lab test first; usually RO
Tanker water	RO with UV, because quality changes load to load
Test shows fluoride, arsenic or nitrate above limits	RO, regardless of TDS

Step 1: Test Your TDS

TDS (total dissolved solids) is the single most useful first number, because it tells you whether RO is even on the table. Start by looking up the typical reading for your pincode, then confirm it with a handheld TDS meter at your own tap. Readings in one building can differ between municipal, borewell and tanker supply.

A TDS meter does not tell you about microbes, fluoride or arsenic. For borewell water, or if anything about your water seems off, get a lab test. Our guide on how to test water quality at home covers meters, kits and when a lab is worth it.

Step 2: Know Your Source

• Municipal (piped) water is treated and usually chlorinated at the plant. TDS is often low to moderate. The main risk is contamination on the way to you: leaking lines, intermittent supply and dirty storage tanks. That is a microbial risk, which UV or UF addresses.
• Borewell water is untreated groundwater. It can be high in TDS and hardness, and in some regions carries fluoride, arsenic, nitrate or iron. It also changes with the seasons. This is where RO is most often justified.
• Tanker water may come from different sources on different days, so you have to plan for the worst load, not the best. RO with UV is the safe default.

Step 3: Compare Against BIS Limits

India’s drinking water standard, BIS IS 10500, gives you the numbers to compare a test against:

Parameter	BIS IS 10500 limit	Treatment if exceeded
TDS	500 mg/L acceptable; 2000 mg/L permissible where no alternative	RO
Total hardness	200 mg/L	RO for drinking; softener for the house
Fluoride	1.0 mg/L	RO
Arsenic	0.01 mg/L	RO
Nitrate	45 mg/L	RO
Iron	0.3 mg/L	Iron removal pre-filter, then purifier

Which Type of Purifier, If Any

• UV: inactivates bacteria and viruses. Needs clear water and electricity. Does not change TDS or remove particles.
• UF: a membrane that physically blocks bacteria, cysts and particles. Works without electricity in many designs. Does not reduce TDS.
• RO: reduces dissolved salts, hardness, fluoride, arsenic and nitrate. Needs power and sends some water to the drain. Usually paired with UV or UF.
• Boiling: a reliable stopgap for microbes, and useful during an outbreak or when travelling. It does not remove dissolved salts or chemicals, and as some water evaporates, those slightly concentrate. Our comparison of boiling water vs an RO purifier covers when each makes sense.

So “which type is best” has no single answer. The right type is the one that treats what your water actually contains.

Do Water Purifiers Really Work?

Yes, for what they are designed to remove, and only while they are maintained. RO does reduce dissolved salts; UV does inactivate microbes in clear water; UF does block bacteria and particles. Where they fail is mismatch and neglect: a UV purifier on high-TDS borewell water leaves the salts untouched, and a purifier running on overdue filters or a failing UV lamp gives a false sense of safety. Check output TDS now and then with a meter, and service on time.

If you have stomach upsets, diarrhoea or other illness that you suspect is linked to water, see a doctor. A purifier is a prevention tool, not a treatment.

Why Salesmen Push RO on Soft Water

It is a fair question. RO units cost more and need more parts replaced over time, so they are worth more to whoever sells and services them. Demonstrations add to the pressure: a TDS meter showing a lower number after RO looks convincing, and colour-changing electrolysis demos show dissolved minerals, not whether water is safe. Lower TDS is not the goal in itself. On soft, low-TDS municipal water, RO removes little that needs removing, wastes some water to the drain, and can leave water tasting flat. Our guide on whether you need RO if your TDS is below 200 sets out that case.

That applies to Boon too. For low-TDS supplies, Boon Tap UF, which has no RO, exists for exactly that situation. For high-TDS, borewell or tanker water, Boon Homie (₹21,900 at the time of writing) and Boon Tap (from ₹23,500) are RO purifiers rated for input up to 2000 TDS, with WaterAI monitoring of input and output TDS and filter health, installed free by Boon’s own team.

Frequently Asked Questions

Do I need a water purifier if I get municipal water?

Usually some treatment, but often not RO. Municipal water is treated at the plant, but it can pick up microbes from leaking lines and storage tanks on the way to you. If your TDS is low and a test shows nothing else above BIS limits, a UV or UF purifier, or boiling, handles the main risk. RO is needed mainly when TDS is high.

Do water purifiers really work?

Yes, for what each technology is designed to remove, as long as it is maintained. RO reduces dissolved salts, fluoride, arsenic and nitrate. UV inactivates bacteria and viruses in clear water. UF blocks bacteria, cysts and particles. Purifiers fail when they are mismatched to the water or run on overdue filters, so test your water and service on time.

What type of water purifier is best for my home?

The one that matches your water. For low-TDS municipal water, UV or UF is usually enough. For TDS above 500, borewell or tanker water, or any test showing fluoride, arsenic or nitrate above BIS limits, choose RO rated for your input TDS, paired with UV or UF. Test your TDS and know your source before choosing.

Why do salesmen push RO purifiers even when municipal water is soft?

RO purifiers cost more and need more replacement parts over time, so they are worth more to the seller. TDS meter and electrolysis demonstrations make lower TDS look like safer water, which it is not by itself. On soft, low-TDS municipal water, RO removes little that needs removing, wastes some water and can make water taste flat.

Is boiling water enough instead of a purifier?

Boiling reliably kills microbes, so it is a good stopgap for low-TDS municipal water, during an outbreak or while travelling. It does not remove dissolved salts, fluoride, arsenic, nitrate or other chemicals, and slightly concentrates them as water evaporates. For high-TDS or borewell water, boiling is not a substitute for an RO purifier.

How do I know if my water needs RO?

Measure your TDS with a meter and compare it to the BIS IS 10500 acceptable limit of 500 mg/L. If it is above that, or your water is from a borewell or tanker, or a lab test shows fluoride above 1.0 mg/L, arsenic above 0.01 mg/L or nitrate above 45 mg/L, you need RO. Below about 200 with nothing else, you usually do not.