Disadvantages of RO Water, and How a Good Purifier Fixes Them

By Sanchit Jain, RO technician and owner of Sanchit Enterprises, Roorkee (since 2014). Updated October 2026.

The main disadvantages of RO water are that the purifier sends some water to drain, removes useful minerals along with harmful salts, can make the water slightly acidic, and needs electricity and regular maintenance. None of these makes RO water unsafe to drink, and each has a practical fix.

We install and service RO purifiers every day in Roorkee and Haridwar. Here is an honest look at each drawback and what we do about it.

6 disadvantages of RO water

1. It wastes water

An RO membrane flushes the salts it removes down the drain, so part of the input water is rejected. The fix: collect the reject water for mopping, washing or plants, and choose a model with better water recovery.

2. It removes minerals

RO removes calcium and magnesium along with harmful salts. The fix: a TDS controller or mineral cartridge, set for your water by a technician.

3. It can be slightly acidic

RO water often tests a little below pH 7. With the minerals gone, the small amount of carbon dioxide dissolved from the air has a bigger effect on pH. This is normal, and a mineral or alkaline stage brings the pH back up.

More disadvantages, and the fixes

4. It is not 100% pure

No home purifier makes water 100% pure. A good RO membrane removes most dissolved solids, typically well over 90%, and the UV or UF stage deals with germs. That is exactly what you want for drinking water.

5. It needs power and maintenance

The pump needs electricity, and filters wear out. Regular RO service or an AMC plan keeps it working.

6. It can be more than you need

If your supply already has low TDS, RO removes more than necessary. A UV or UV+UF purifier may be enough. Test first.

Is RO water 100% pure?

No, and it does not need to be. The Indian drinking water standard, BIS IS 10500, sets limits that safe water must stay within, including 500 mg/L of total dissolved solids and a pH between 6.5 and 8.5. A well-set RO keeps your water within those limits while leaving it pleasant to drink.

Can I drink RO water every day? Can I boil it?

Yes, you can drink RO water every day. A purifier that is serviced on time, with a clean tank and the TDS set correctly, gives safe drinking water.

You do not need to boil RO water if the UV or UF stage is working. Boiling does no harm, and it is a good backup if the purifier has not been serviced for a long time or the UV lamp has failed. Boiling does not reduce TDS.

Weighing up the disadvantages of RO water

The disadvantages of RO water are real but manageable. For high-TDS borewell water, common around Roorkee, RO is still the most practical way to get safe, good-tasting water at home. The key is a purifier set for your water and serviced on time. If you are unsure whether you need RO at all, read is RO water good for health.

Disadvantages of RO water: frequently asked questions

Is RO water acidic?

It is often slightly below pH 7 because minerals are removed. A mineral or alkaline stage raises the pH.

Is RO water 100% pure?

No home purifier gives 100% pure water. A good RO removes most dissolved solids and keeps water within BIS limits.

Can I boil RO water to drink?

Yes. It is not needed when the purifier is serviced and the UV works, but it does no harm.

How can I reduce RO water wastage?

Reuse the reject water for cleaning or plants, and choose a model with better recovery.

Related: RO service in Roorkee · water purifier dealer in Roorkee · RO AMC plans

More RO guides: RO vs alkaline water · RO not giving water? 7 causes · Is RO water good for health? · RO water wastage