How often to change a water filter depends on the type: pitcher filters typically last 1 to 6 months, faucet filters 2 to 3 months, under-sink and refrigerator filters about 6 months, and reverse osmosis membranes 2 to 3 years with pre-filters changed more often. The real guide is the manufacturer’s gallon rating and how your water tastes and flows. Changing filters on schedule keeps them safe and effective. This guide explains how often to change each type of water filter.
Pitcher filters last 1 to 6 months, faucet 2 to 3 months, under-sink and fridge filters about 6 months, and RO membranes 2 to 3 years (pre-filters more often). Follow the gallon rating, and change sooner if taste or flow worsens.
How Often to Change by Type
| Filter type | Typical change interval |
|---|---|
| Pitcher (standard) | 1-2 months (or ~40 gallons) |
| Pitcher (long-life) | ~6 months (or ~120 gallons) |
| Faucet filter | 2-3 months (or ~100 gallons) |
| Under-sink carbon | ~6-12 months |
| Refrigerator filter | ~6 months |
| RO pre-filters / membrane | 6-12 months / 2-3 years |
Key Takeaway: Go by gallons, not just the calendar. A filter’s life is rated in gallons, so a heavy-use household hits the limit sooner than a light one. When taste returns or flow slows noticeably, the filter is spent regardless of the date.
Why Changing on Schedule Matters
An overused filter stops working and can even harbour bacteria. Changing on schedule keeps the water safe and effective, and keeps flow up. See why your filter is slow.
Signs a Filter Needs Changing
- Taste or odour returns (chlorine taste back).
- Flow slows noticeably.
- The filter indicator (if fitted) says so.
- You have passed the gallon rating or time interval.
Tips
- Follow the manufacturer’s gallon rating and interval.
- Track usage if you drink a lot of filtered water.
- Flush new filters before use as directed.
- Keep spare filters on hand.
See how long water filters last.
FAQ
How often should you change a water filter?
It depends on type: pitcher 1 to 6 months, faucet 2 to 3 months, under-sink and fridge about 6 months, RO membranes 2 to 3 years. Follow the gallon rating and change sooner if taste or flow worsens.
What happens if you do not change a water filter?
It stops filtering effectively, taste returns, flow slows, and it can harbour bacteria. Change filters on schedule for safe, effective water.
How do you know when to change a water filter?
When taste or odour returns, flow slows, the indicator says so, or you pass the gallon rating or time interval.
Bottom Line
Change a water filter on its gallon rating and interval: pitchers every 1 to 6 months, faucet filters every 2 to 3, under-sink and fridge filters about every 6, and RO membranes every 2 to 3 years. Change sooner if taste or flow worsens. See our how long water filters last guide.
