Learn · 4 min read
How Often Should You Replace a Whole-House Water Filter?
Cartridge systems (the 4.5" by 20" multi-stage units from iSpring, Aquasana Rhino, or Pentair) need new cartridges every 6 to 12 months. Sediment cartridges go first, especially on well water. Carbon-block cartridges follow shortly after.
Tank-style catalytic carbon (SpringWell CF, SoftPro Carbon) lasts 6 to 10 years on city water before the media is exhausted. There is no annual cartridge cost. You replace the entire media bed at the end of its life.
Salt-based softener resin lasts 10 to 15 years on properly pre-filtered water. The thing you actually refill monthly is the salt in the brine tank, not the resin.
Salt-free TAC conditioners need a media bed swap every 5 to 6 years. They do not regenerate, so there is nothing to do between replacements.
UV lamps are replaced annually regardless of how the water looks. Output drops below the certified disinfection dose long before the lamp visibly burns out.
Reverse osmosis units have three or four filters on different schedules: pre-filters every 6 to 12 months, post-carbon every 12 months, and the RO membrane itself every 2 to 4 years.
Recommended products that solve this
If this is your situation, these are the systems we recommend. Buttons open the brand's current pricing in a new tab.
Top pick
SpringWell
SpringWell CF1 Whole House Filter
Whole-house carbon filter
Tank-style catalytic carbon with a 6 to 10 year media life on city water, no annual cartridge cost to track.
Also consider
iSpring
iSpring WGB32B 3-Stage
Whole-house cartridge filter
Cartridge-style 3-stage example if you prefer the cheaper upfront price and yearly cartridge swaps.
Frequently asked questions
- How often do cartridge filters need to be replaced?
- Every 6 to 12 months for most 4.5" by 20" multi-stage systems. Sediment cartridges go first, especially on well water, then carbon-block cartridges shortly after.
- How long does tank-style carbon media last?
- 6 to 10 years on city water before the full media bed is exhausted. There is no annual cartridge cost in between, just periodic backwash cycles.
- Do I need to replace softener resin every year?
- No. Properly pre-filtered softener resin lasts 10 to 15 years. The thing you refill monthly is the salt in the brine tank, not the resin itself.
- How often should a UV lamp be replaced?
- Annually, regardless of how the water looks. UV output drops below the certified disinfection dose long before the lamp visibly burns out.