Filter Replacement
An expired filter can stop working without an obvious sign. Replacement schedules matter more than they seem.
Short answer: Follow the manufacturer's specific replacement schedule for your model, based on gallons filtered or a maximum time interval, whichever comes first. Don't wait for a visible sign like slow flow or bad taste, since some contaminant-specific media can fail silently.
Typical replacement signals
- Manufacturer-specified gallon count reached
- Manufacturer-specified time interval reached (e.g., every 6 months), even if gallon count is lower
- Noticeable reduction in flow (a sign for sediment filters, but not a reliable signal for contaminant-specific media)
- Return of the original taste, odor, or issue the filter was addressing
Step-by-step
- Find your specific filter or cartridge's rated capacity and time interval.
- Set a calendar reminder rather than relying on noticing a problem.
- Keep a simple log of replacement dates, especially for whole-house or facility systems.
- For lead- or PFAS-specific media, replace on schedule regardless of visible performance, since breakthrough isn't always obvious.
Common mistakes
- Waiting for a visible sign of failure before replacing contaminant-specific media
- Assuming all filter types share the same replacement interval
- Not keeping a written log for systems with multiple cartridges
Official sources
- Manufacturer documentation for your specific filter model
- NSF/ANSI certification documentation, which includes rated capacity
Related
Can I just wait until the water tastes bad again?
Not for contaminant-specific media like lead or PFAS filters — taste and odor aren't reliable indicators for those contaminants. Follow the manufacturer's rated schedule instead.
Does not endorse a specific manufacturer or product claim.
Last reviewed: 2026-07-11. Report a correction.