Filter Maintenance Schedules
A filter past its lifespan can release captured contaminants back into water or air. Schedules vary by type, usage, and source quality.
Water filters
Pitcher carbon (Brita, PUR)
Every 2 months or 40 gal. $7-$12/filter, ~$42-$72/year. Signs: slower flow, chlorine taste returns.
Under-sink carbon block
Every 6-12 months or 500-1,000 gal. $30-$60/cartridge, $60-$120/year. Signs: pressure drop, taste change, flow below 50% of original.
Reverse osmosis
Membrane every 2-3 years ($40-$80). Pre/post filters every 6-12 months ($15-$30 each). Total ~$60-$120/year. Signs: TDS creep above 10% of input.
Air purifier filters
HEPA
Every 6-12 months. Heavy use (pets, wildfire) shortens to 4-6 months. $30-$80. Signs: visibly clogged, reduced airflow, increased noise.
Activated carbon
Every 3-6 months. $15-$40. Saturated carbon off-gasses captured VOCs. If odors return, carbon is spent.
Pre-filter
Vacuum/rinse monthly. Replace every 3 months if disposable. $5-$15. Clean pre-filter doubles HEPA lifespan.
Annual cost summary
Pitcher: $42-$72/year
Under-sink carbon: $60-$120/year
RO system: $60-$120/year (membrane averaged)
Air purifier (HEPA + carbon): $60-$150/year
Budget for replacements when you buy the unit. The filter is the ongoing cost.