Whole-House Filter Sizing Calculator

An undersized whole-house filter causes pressure drops, slow showers, and premature filter wear. Enter your home's fixtures and usage pattern to find the right GPM rating.

Your Home's Fixtures

Bathrooms

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Kitchens

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DishwasherAdds 1.5 GPM when running

Washing machineAdds 2.0 GPM when running

Outdoor hose bibAdds 5.0 GPM - significant impact on sizing

Usage pattern

NormalTypical single-family use - rarely more than 2 fixtures running at onceHeavyLarger family or frequent simultaneous use - 3+ fixtures at onceVery HeavyLarge household, irrigation, or pool fill - near-constant demand

Sizing Recommendation

10.0

Total fixture GPM

6.0

Service flow GPM

9.0

Peak flow GPM

0.75"

Recommended port

How we calculated this: Your fixtures total 10.0 GPM if everything ran simultaneously. With a normal usage pattern (60% simultaneous use factor), your required service flow is 6.0 GPM. We recommend a system rated for at least 9.0 GPM peak (1.5x service flow) with 3/4" ports.

Compatible Whole-House Filters

Aquasana Rhino EQ-1000

7 GPM service · 14.6 GPM peak · 0.75" port

$1,598.00

Replacement filters: $111.00/yr

Buy on Amazon →

SpringWell CF1

9 GPM service · GPM peak · 1" port

$810.00

Replacement filters: $40.00/yr

Buy on Amazon →

SpringWell CF4

12 GPM service · GPM peak · 1" port

$1,020.00

Replacement filters: $40.00/yr

Buy on Amazon →

Pelican PC600

8 GPM service · 12 GPM peak · 0.75" port

$828.00

Replacement filters: $65.00/yr

Buy on Amazon →

Express Water WH300SCKS

15 GPM service · GPM peak · 1" port

$548.00

Replacement filters: $90.00/yr

Buy on Amazon →

iSpring WGB32B

15 GPM service · GPM peak · 1" port

$350.00

Replacement filters: $126.00/yr

Buy on Amazon →

SpringWell CSF1 Combo

9 GPM service · GPM peak · 1" port

$1,597.00

Replacement filters: $40.00/yr

Buy on Amazon →

ℹ️ Flow rate estimates based on standard fixture rates - consult a licensed plumber for precise sizing.