How whole-house RO differs
Under-sink RO treats a small volume for one faucet. Whole-house RO treats all the water a home uses, so it is larger and has extra parts: a storage tank because membranes produce water slowly, a pump to push treated water back through the house at normal pressure, and often post-treatment because RO water is low in minerals. It also sends concentrate to drain, and the EPA notes even point-of-use RO sends water to drain for every gallon treated. These systems are less common in homes; many city-water homes use whole-home filtration and softening instead. See whole-house filtration vs reverse osmosis.
Weekly to monthly checks
- Log readings: feed pressure, pressure after pre-filters, membrane outlet pressure, and TDS of feed and product water. Trends tell you more than single readings.
- Check flows: product and concentrate flow, if the system has meters.
- Look for leaks at housings, fittings, the tank and the pump.
- Listen to the pump: frequent short cycling or new noises need attention.
- Check the drain: the concentrate line and air gap should be clear and discharging where permitted.
Scheduled maintenance
| Item | Trigger |
|---|---|
| Sediment and carbon pre-filters | Manufacturer interval or pressure drop across the housing |
| Softener or antiscalant feed (if used) | Salt or chemical level, regeneration settings |
| Membrane cleaning | Falling product flow or rising TDS against your baseline |
| Membrane replacement | When cleaning no longer restores performance |
| Storage tank sanitizing | Manufacturer schedule |
| UV lamp (if installed) | Manufacturer interval; clean the sleeve |
| Post-treatment media | pH of product water drifting |
Pre-treatment is the whole game
Membranes fail early when pre-treatment slips. Chlorine and chloramine can damage many membranes, hardness and iron can scale or foul them, and sediment clogs them. On wells, iron, manganese and hydrogen sulfide usually need their own treatment before RO. If any pre-treatment stage is overdue, fix that first. See sediment filtration and iron testing.
Signs to call for service
- Product TDS rising steadily.
- Storage tank not refilling or low pressure at fixtures.
- Pump running constantly.
- Unusual taste or odor from the treated water.
- Water on the floor around equipment.
For the drinking-water-only version of this checklist, see how often to replace RO filters. For ownership costs, read RO maintenance and operating costs.
Keep a startup baseline
The single most useful record is the set of readings taken when the system was commissioned: feed and product TDS, pressures at each gauge, product and concentrate flow, and product water pH. Every later reading is compared against it. Ask your installer to write these down and leave a copy at the equipment. Without a baseline, it is hard to tell whether a membrane needs cleaning or whether readings are simply normal for your water. Living Water's city water systems and well water systems are configured from a test, so ask Jorge which approach fits your home.
https://www.epa.gov/watersense/point-use-reverse-osmosis-systems
https://www.epa.gov/system/files/documents/2025-01/ws-products-home-water-treatment-guide_v2_508.pdf
https://www.epa.gov/dwreginfo/chloramines-drinking-water
https://www.floridahealth.gov/community-environmental-public-health/environmental-public-health/water-quality/drinking-water/private-wells/
Updated 2026-10-17 · Living Waters · Jorge Canela, Water Quality Specialist