service · Pan-India
RO Water Wastage: How Much You Lose & How to Reduce It
A conventional domestic RO discards roughly 3 litres for every 1 litre it purifies. For a family drinking 15 litres a day, that is about 45 litres a day and over 16,000 litres a year — and if you buy tanker water, it is a line on your monthly bill.
There are two things you can do about it, and you should do both. Buy a high-recovery model, which roughly halves the loss. And plumb the reject line into a bucket or drum, because reject water is not sewage — it is simply your supply water, more concentrated.
Indicative charges
| Design | Reject ratio | Daily loss (15 L purified) | Annual loss |
|---|---|---|---|
| Conventional RO | 3:1 | ~45 litres | ~16,400 litres |
| Improved recovery | 2:1 | ~30 litres | ~11,000 litres |
| High recovery (KENT Save Water, AO Smith ART) | 1:1 | ~15 litres | ~5,500 litres |
| UV + UF (no RO) | 0 | 0 | 0 |
These are indicative market ranges across India, useful for sanity-checking a quote. Actual charges vary by city, brand and whether parts are genuine or third-party. Franchisee pricing for the same service differs meaningfully between cities — always get the quote in writing before work starts.
Safe and unsafe uses for RO reject water
- GOOD — floor mopping and general cleaning.
- GOOD — toilet flushing, if you can route it to a storage drum near the bathroom.
- GOOD — washing vehicles and outdoor areas.
- GOOD — pre-rinsing utensils before the final rinse in fresh water.
- CAUTION — plants. Reject water is 2-4 times more concentrated in dissolved salts than your supply, and on hard water those salts accumulate in the soil and will eventually harm plants. Safe only if your input TDS is genuinely low.
- NEVER — drinking, cooking, or filling pet water bowls.
Tip
The most water-efficient decision of all
If your supply is treated municipal water below about 200 ppm TDS, the highest-impact water saving available to you is not buying an RO in the first place. A UV+UF purifier wastes nothing, retains minerals, costs less to run, and handles the microbiological risk that is actually present in treated supply.
A great deal of Indian RO ownership is solving a problem the household does not have, at the cost of thousands of litres a year. Measure your TDS before you buy.