H2O Insider

Whole-House Filter Cartridge Replacement

Whole-house sediment filters: every 3-6 months. Carbon blocks: every 6-12 months. KDF and catalytic carbon: every 12-18 months. Full schedule and cost analysis.

Whole-House Cartridge Sizing and Selection

Whole-house filter cartridges handle every gallon of water entering a home — shower, laundry, irrigation, and drinking water. The volume demands are 10-50× higher than a point-of-use filter, which means cartridge capacity, pressure drop, and replacement cost have far greater impact on both performance and budget. Undersizing a cartridge (using a 10" sediment filter where a 20" Big Blue is needed) creates pressure drop that customers experience as reduced shower flow — and a clogged filter left in place is worse than no filter.

Cartridge Selection by Housing and Application

ApplicationSize NeededRecommended CartridgePriceInterval
City water sediment pre-filter4.5"×20"Pentek R50-BB 50-micron polypropylene$126 months
City water chlorine/taste4.5"×20"Pentek ChlorPlus20-BB catalytic carbon block (NSF 42)$6012 months
City water chloramine treatment4.5"×20"Pentek ChlorPlus10-BB catalytic carbon (required for chloramine, not standard GAC)$5512 months
Well water coarse sediment4.5"×20"Pentek R30-BB 30-micron polypropylene$103-6 months (well-dependent)
Well water fine sediment (pre-UV)4.5"×10"Pentek S1-BB 1-micron sediment (clear housing allows inspection)$142-3 months with heavy sediment
Well water iron/manganese4.5"×20"Pentek RFFE20-BB iron reduction media$456-12 months (based on iron loading)
SpringWell CF1 annual serviceCF1-specificSpringWell CF1 Annual Maintenance Kit$7812 months (includes KDF+carbon media replacement)
Aquasana Rhino whole-houseRhino-specificAquasana EQ-600-R replacement bundle$9812 months / 600,000 gal rated

Maintenance Schedule by System Type

Standard 10" single-stage (city water)

Every 3 monthsInspect and replace 5-micron sediment cartridge ($8)
Every 6 monthsReplace carbon block cartridge ($20-35); check O-rings on housing cap
AnnuallySanitize housing with dilute bleach solution; inspect inlet/outlet pressure gauge readings

Estimated annual cartridge cost: $80-120

Big Blue 20" dual-stage (city water)

Every 6 monthsReplace sediment pre-filter cartridge ($10-15)
Every 12 monthsReplace catalytic carbon cartridge ($55-65); check pressure differential
Every 2 yearsReplace O-rings in housing cap; inspect fittings for leaks

Estimated annual cartridge cost: $90-120

3-stage well water system (sediment → carbon → UV)

Every 2-3 monthsInspect and replace coarse sediment cartridge ($10) — well-dependent
Every 6 monthsReplace fine sediment pre-filter ($14) and clean UV quartz sleeve
Every 12 monthsReplace carbon cartridge ($25-55) and UV lamp regardless of apparent function ($60)
AnnuallyRetest well water to confirm treatment is still effective against current contamination

Estimated annual cartridge cost: $180-280

Install a Pressure Gauge on Your Whole-House Housing

A $12 pressure gauge installed upstream and downstream of your whole-house housing gives you a real-time indicator of cartridge exhaustion. A pressure differential above 10 psi means the cartridge is restricting flow — replace immediately. A differential below 1 psi either means the cartridge is nearly new or has channeled (water is flowing around the media, not through it). Both the gauge upstream and the one downstream pay for themselves in avoided pressure problems and in knowing exactly when to replace rather than guessing by calendar.

Frequently Asked Questions