An RO (reverse osmosis) water purifier doesn’t run continuously – its pump only switches on to push water through the membrane and refill the storage tank, then shuts off automatically once the tank is full. That makes its electricity cost much lower than most people assume. Our free RO Water Purifier Running Cost Calculator below shows you the daily, monthly and yearly running cost, plus the cost per liter of purified water.
RO Water Purifier Running Cost Calculator
RO Water Purifier Running Cost Calculator
Check the adapter/rating label – most under-sink RO purifiers with a booster pump use 40-70W.
Total minutes the pump actually runs across the day, not how long the unit is plugged in. A typical household purifying 15-20 liters/day runs its pump 15-30 minutes total.
Auto-filled with a typical average – edit to match your own bill.
How Much Electricity Does an RO Water Purifier Use?
An RO purifier’s booster pump only runs when the storage tank needs refilling – it’s not continuous like a fridge. The formula is:
Cost = (Wattage / 1000) x (Pump Minutes Per Day / 60) x Electricity Rate per kWh
Because the pump typically only runs 15-30 minutes total per day even in a busy household, RO purifiers are one of the cheapest appliances to run electrically – the real ongoing cost of RO water is usually dominated by filter/membrane replacement, not electricity.
RO Purifier Running Cost by Usage
| Household Size | Water/Day | Pump Runtime/Day | Monthly Cost (Rs 8/kWh) |
|---|---|---|---|
| 1-2 people | 5-8 liters | ~8 min | ~Rs 19 |
| 3-4 people | 12-18 liters | ~18 min | ~Rs 43 |
| 5-6 people | 20-28 liters | ~28 min | ~Rs 67 |
Estimates use a 60W purifier at Rs 8/kWh. Actual pump runtime varies with source water pressure and membrane condition.
Tips to Keep RO Running Costs Low
- Replace pre-filters on schedule – clogged sediment/carbon filters make the pump work harder and longer to fill the tank, raising electricity use.
- Check for tank leaks – a leaking storage tank makes the pump cycle on far more often than necessary, wasting both water and electricity.
- Maintain adequate inlet water pressure – low input pressure forces the booster pump to run longer per fill; a pressure booster or corrected plumbing can cut runtime.
- Don’t ignore RO reject water – while not an electricity cost, reusing reject water for cleaning/plants improves the overall economics of running an RO system.
Frequently Asked Questions
How many watts does an RO water purifier use?
Most under-sink or countertop RO purifiers with a booster pump use 40-70W while the pump is actively running. The pump does not run continuously.
Does an RO purifier run all the time?
No. The booster pump only switches on to refill the storage tank when it drops below a certain level, then automatically shuts off once full – typically 15-30 minutes of total runtime per day for a household.
How much does it cost to run an RO purifier per month?
For a typical household using 12-18 liters/day, electricity cost is roughly Rs 40-45 per month in India at Rs 8/kWh – a small fraction of most other appliance running costs.
Is electricity the main cost of RO water?
No. Electricity is a minor cost. The dominant ongoing cost is filter and membrane replacement (typically every 6-12 months), which usually costs far more than a year of the pump’s electricity use.
Does water pressure affect RO running cost?
Yes. Low inlet water pressure forces the booster pump to run longer to fill the tank, which increases electricity use and can also shorten pump life.
Why is my RO purifier’s pump running more than usual?
Common causes include a clogged pre-filter, a leaking storage tank, a failing check valve, or dropping input water pressure – any of these force the pump to cycle on more frequently.