Solutions by situation
Borewell water — the tests that decide everything else
The problem
Borewell water is not one thing. Two wells a hundred metres apart, drilled to different depths, can differ by an order of magnitude in iron, hardness, fluoride and arsenic.
That variability is why the standard advice — 'borewell water needs RO' — is both usually right and dangerously incomplete. RO fitted to iron-bearing water fouls within months, and the household ends up replacing membranes repeatedly while nobody tests the feed.
The other half of the problem is what a TDS meter shows: a large number that says nothing about which of the four parameters that matter is actually present.
What this situation actually needs
Requirements first, in the order they matter. Note that several of these are not products.
Iron below the RO manufacturer's feed limit
Iron fouls membranes irreversibly. Most units specify a maximum feed iron around 0.1–0.3 mg/L.
Oxidation plus backwashing media filter ahead of the RO where iron exceeds the limit
Hardness controlled if scale is a complaint
Hardness damages geysers and washing machines, which are not fed from the drinking-water tap.
Whole-house ion exchange softener on the inlet, sized to the measured hardness
Nitrate below 45 mg/L as NO₃
The most widespread agricultural contaminant in Indian groundwater, and it does not resolve on its own.
RO, which rejects nitrate at 85–95%
Regional contaminants ruled in or out
Fluoride and arsenic are geographically concentrated and are not in a standard water panel unless asked for.
Laboratory test by name; RO with pre-oxidation for arsenic, RO or activated alumina for fluoride
Turbidity controlled before any UV stage
Turbid water shields organisms from UV, so the lamp runs while the dose collapses.
Staged sediment filtration, 20 µm ahead of 5 µm
The specification
Written as a specification rather than a product name, deliberately. A specification survives a model being discontinued and can be taken to any shop; a product recommendation expires.
| Attribute | Target | Why |
|---|---|---|
| Order of installation | Sediment → iron removal → softener → RO → UV | Each stage protects the next. Getting the order wrong is the commonest expensive mistake on borewell water |
| Pre-treatment | Sized to measured iron and hardness, not assumed | Undersized pre-treatment is the reason membranes die early |
| RO membrane | Standard domestic up to ~2,000 ppm feed; brackish-water membrane above | Beyond its design envelope, recovery collapses and membrane life shortens |
| Verification | Feed and product TDS measured at installation and annually | Rejection falls silently; nothing on the unit reports it |
| Consumables | Expect shorter pre-filter intervals than the box states | Turbidity and iron load pre-filters far faster than clean municipal supply |
What to avoid
In every one of these situations there is a purchase that looks obviously right and is wrong.
Installing RO before testing for iron
A ₹250 test ahead of a ₹15,000 purchase. Skipping it is how households end up on their third membrane in two years without anyone diagnosing why.
Buying a drinking-water purifier to solve a scale problem
Scale forms in your geyser and washing machine, which are fed from the untreated line. A point-of-use purifier treats around 1% of household water.
Accepting a quotation with no water analysis
Pre-treatment sizing depends entirely on the numbers. A vendor quoting without them is guessing, and the guess is priced in your favour or theirs, not neutrally.
Relying on a TDS reading to characterise borewell water
The parameters that matter most on groundwater — iron, fluoride, arsenic, nitrate — are all either invisible to the meter or indistinguishable from harmless minerals.
Frequently asked questions
Which water purifier is best for borewell water?
Why does my RO membrane keep failing on borewell water?
Do I need a softener as well as an RO for borewell water?
Budget bands are indicative Indian market ranges for planning, last reviewed 2026-08-08. Where this page recommends a test before a purchase, that ordering is deliberate — the specification depends on the result, and a recommendation made without one is a guess wearing a table.