RO & Drinking Water Tips for a Delhi Home

1. Know your TDS number — both of them

A handheld TDS meter is inexpensive and it turns every future conversation about your purifier from an argument into a measurement.

• Measure the water going in (a tap before the purifier) and the water coming out. Write both down with the date.
• A healthy membrane produces a large drop between the two. A small drop means the membrane is failing or being bypassed.
• Re-measure every few months. A gradually rising output figure is your early warning — long before the water tastes different.
• Very low output TDS is not automatically better. Water with almost nothing dissolved in it tastes flat, which is why many units add minerals back.

Our RO service and TDS guide covers what the numbers mean, and having your own reading is the best defence against being sold a membrane you do not need — see the RO repair guide.

2. Change the cheap filters on time

Sediment and carbon pre-filters are consumables, and they exist to protect the expensive part.

• In Delhi water most homes need them every six to twelve months, at the shorter end if you are on borewell supply or an old building.
• A choked pre-filter starves the pump, and a starved pump is a common cause of “no water” that gets misdiagnosed as something worse.
• It also lets sediment reach the membrane, which shortens the life of the one part you really do not want to replace early.
• Write the change date on the housing with a marker. Nobody remembers otherwise.

Our filter change guide covers the schedule in more detail.

3. The problem is often upstream of the purifier

This is the part people miss entirely. Your RO is the last thing the water passes through, not the first.

• The overhead tank. If it has not been cleaned in years, your purifier is filtering sediment that did not need to be there, and the pre-filters pay for it. Our tank cleaning guide covers it.
• The tank lid. An unsealed lid lets in dust, leaves and insects. A five-minute check.
• Old galvanised pipes shed rust, which is why some homes see filters discolour far faster than others in the same building.
• Hard water generally — see our hard water tips for the wider picture, because the same water is scaling your geyser and taps too.

4. The purifier’s own storage tank needs attention

Almost nobody thinks about the small tank inside the purifier, and it is the last surface the water touches before you drink it.

• Ask for it to be cleaned during the annual service. A technician who never opens it is not doing a full service.
• If you are away for a week or more, run a few litres through and discard them when you return rather than drinking water that has been standing.
• A musty taste with a normal TDS reading usually points at the tank or the tubing, not the membrane.
• Keep the unit out of direct sunlight. Light plus standing water encourages growth in the tubing.

5. Two habits worth having

• Do not switch the unit off at the socket for long periods. Most units manage their own cycle; leaving water standing in a dead unit for weeks is worse than letting it run.
• Note what normal sounds like. An RO makes a recognisable pattern of pump and flush noise. When that pattern changes — running constantly, cycling repeatedly, never stopping — that is usually the first sign of a fault, and it arrives well before the water quality changes.

If it has already stopped working, start with our RO not working guide before calling anyone.