How long does a reverse osmosis system last?
Updated August 2026
An under-sink reverse osmosis system lasts 10–15 years as a unit, but it is really a stack of parts on very different clocks. The RO membrane, the heart that strips out contaminants, lasts 2–5 years; the pre-filters and post-filter that protect it need swapping every 6–12 months. Skip those cheap filter changes and the pricey membrane clogs and dies early, dragging the whole system down with it. Keep up with them and give the unit decent water pressure, and the tank, valves, and housings run the full 10 to 15 years.
Lifespan by type and situation
| Type or situation | Typical lifespan | Why |
|---|---|---|
| Full RO system (tank, valves, housings) | 10–15 years | The frame outlasts many filter cycles |
| RO membrane | 2–5 years | Lasts longest when the pre-filters stay fresh |
| Sediment and carbon pre-filters | 6–12 months | Protect the membrane; the cheapest routine swap |
| Post or polishing filter | 6–12 months | Final taste-and-odor stage before the tap |
| Storage tank bladder | 8–15 years | A waterlogged tank means a slow trickle at the faucet |
| Low incoming pressure | Shortens membrane | Under 40 psi the membrane fouls and output drops |
Signs yours is near the end
- A noticeable drop in flow at the RO faucet, or a tank that fills slowly
- Water that tastes or smells off, a sign the filters or membrane are spent
- The system running or draining to waste far more than usual
- A total dissolved solids (TDS) meter reading that keeps climbing
- Leaks at the housings, fittings, or the tank connection
- Filters or membrane long past their 6–12 month or 2–5 year windows
How to add years
Everything hinges on the filter schedule. Change the sediment and carbon pre-filters every 6–12 months so they keep chlorine and grit off the membrane, which is exactly what lets a $50–100 membrane reach 3–5 years instead of dying in one. Swap the post-filter on the same visit, and sanitize the housings and tank once a year while you have it open. Make sure incoming pressure is at least 40 psi, since a starved membrane fouls fast; a small booster pump fixes low-pressure homes. A cheap TDS meter tells you when the membrane is finally slipping. Put the filter dates on a maintenance checklist with your other how-often tasks so the cheap swaps never lapse and cost you the expensive part.
What it costs to replace: plan on $200–600 installed. Replacing on your own schedule, before it fails, is almost always cheaper than the emergency version. The home maintenance cost calculator helps you set the money aside before it comes due.
OnOtto tracks your RO filter changes age and service history, and warns you before end of life instead of after the flood.
Track your home's systems, free for 30 daysFrequently asked questions
How often do I need to change reverse osmosis filters?
The pre-filters and post-filter every 6–12 months, and the membrane every 2–5 years. Sediment and carbon pre-filters clog first because they take the brunt of the incoming water, and a spent carbon filter lets chlorine through to attack the membrane. Homes with dirtier or harder water lean toward the 6-month end; clean municipal water can stretch closer to a year. Missing these swaps is the number-one reason a membrane dies early, so the cheap filters are what protect the expensive part.
How long does an RO membrane last?
Two to five years, if you keep the pre-filters fresh. The membrane is a fine semipermeable film that slowly fouls with minerals and any chlorine that slips past a worn carbon filter, so its life is tied directly to the filters ahead of it. A rising total-dissolved-solids reading or a steady drop in water quality tells you it is time. In very hard water or with skipped filter changes it can clog in a year; in soft, well-filtered water it can reach five.
Why is my reverse osmosis system slow or barely trickling?
Usually one of three things: clogged filters, a waterlogged storage tank, or low pressure. Filters past their 6–12 month window choke the flow first, so change those before anything else. If the tank feels heavy and full but only trickles out, its internal bladder has lost its air charge and needs recharging or replacing. And if incoming pressure is under about 40 psi, the membrane simply cannot push enough water, which a small booster pump solves. Check filters, then tank, then pressure.
Is a reverse osmosis system worth the upkeep?
For most homes on questionable or hard water, yes. The running cost is modest, roughly $50–150 a year in replacement filters plus a membrane every few years, against bottled water or the taste and contaminants you are trying to remove. The one real chore is remembering the filter swaps, since a neglected system quietly loses effectiveness and can breed the very problems it was meant to fix. If you will keep up the 6–12 month schedule, an RO unit pays for itself; if not, it is money for a clogged box under the sink.