Choosing a Water Purifier for a Delhi Home

1. Test your supply before you shop

• Get a TDS reading. A TDS meter costs very little, or any RO technician will test it for a small charge. It measures total dissolved solids — the mineral and salt load.
• Test at different times. Many Delhi homes run on tanker supply some days and mains on others, and the two can be quite different. One reading on one day is not your water.
• Note what you can observe. Does it leave white scale on the kettle and taps? Is there visible sediment after a supply interruption? Any smell? These tell you about hardness and particulates that a TDS number alone does not.
• Ask your neighbours. On the same supply, their experience is directly relevant — including which units they have had trouble with.
• Find out your source. Municipal supply, borewell, tanker, or a mix. Borewell water in parts of NCR runs notably harder.

Our RO service and TDS guide explains what the readings mean.

2. RO, UV, UF — what each one is for

These address different problems, and the marketing tends to blur that.

• RO reduces dissolved solids — salts, heavy metals, hardness. It is the answer to high TDS. It also wastes some water as reject, which is by design.
• UV deals with microbiological contamination. It does nothing to dissolved solids, so on high-TDS water it is not a substitute for RO.
• UF filters particulates and some microbes without electricity and without reject water, which makes it useful where supply is low-TDS but unreliable.
• Combination units are common because most Delhi supplies want more than one of these. Which combination depends on your reading — not on which has the most acronyms on the box.
• If your TDS is genuinely low, RO may not be necessary at all, and stripping the water further affects taste. This is worth knowing before being sold the largest unit in the shop.

Our RO vs UV guide goes through the decision in detail.

3. The practical things people overlook

• Storage tank size versus your supply. If your water comes for two hours a day, a bigger storage tank matters far more than any specification on the box. This is the most commonly overlooked point in Delhi.
• Where will it go, and is there a drain? An RO needs a power socket, an inlet and somewhere for the reject line to discharge. Sorting this out after delivery is a bad afternoon.
• Wall strength. A full unit is heavy. A hollow partition wall may need proper anchoring.
• Can you reach the filters? A unit tucked into a tight cabinet is a unit that is awkward to service, and awkward servicing is servicing that gets postponed.
• Is service available locally? A brand with no technician in your area is a purifier that stays broken. Worth asking before buying, not after.

4. Budget the running cost, not just the purchase

The purifier is the smaller half of what you will spend on it. Filters and membranes are consumables and they are not optional.

• Ask the price of the filters and membrane before buying the unit. They vary considerably between models, and a cheaper purifier with expensive proprietary consumables is not the cheaper purifier.
• Ask whether generic parts fit or whether it is a closed system. This decides your options for years.
• Factor in your TDS. Harder water means filters and membranes work harder and are replaced sooner — our filter change guide covers the schedule.
• Decide about an AMC after the warranty, not during it. Paying for a contract while the manufacturer still covers the unit is paying twice — our AMC guide has the arithmetic.
• Keep a log from day one. Install date, filter changes, TDS in and out. It takes seconds and it is the only real evidence of how the unit is performing.

Our drinking water tips cover looking after it once it is in, and the hard water tips cover what the same water is doing to the rest of your home.