Monroe, WA water hardness

Tap water hardness
29mg/L
1.7gpg
SoftCounty estimate

County estimate from 33,817 water samples in Snohomish County · July 2026

WA typical
36 mg/L
EPA health violations since 2016
0
Data
County estimate

Water samples from around Monroe put hardness at about 29 mg/L (1.7 gpg), which would be soft on the USGS scale. Treat this as a rough guide: it is the median of 33,817 samples taken across Snohomish County, mostly wells and streams, not a test of Monroe's treated tap water. One more reason for caution: EPA lists Monroe's water system as using surface water, which is often softer than the wells behind the county figure.

Monroe on the hardness scale, with nearby cities
060120180240300360+WA typical 36Mill Creek East: 13 mg/LMill Creek East 13Bothell East: 13 mg/LBothell East 13Mill Creek: 13 mg/LMill Creek 13Maltby: 16 mg/LMaltby 16Duvall: 21 mg/LDuvall 21Eastmont: 22 mg/LEastmont 22Cottage Lake: 25 mg/LCottage Lake 25Woodinville: 25 mg/LWoodinville 25Snohomish: 36 mg/LSnohomish 36Silver Firs: 43 mg/LSilver Firs 43Monroe 29mg/L as calcium carbonate060120180240300360+WA 36Maltby: 16 mg/LMaltby 16Duvall: 21 mg/LDuvall 21Eastmont: 22 mg/LEastmont 22Cottage Lake: 25 mg/LCottage La. 25Snohomish: 36 mg/LSnohomish 36Silver Firs: 43 mg/LSilver Firs 4329 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Monroe sits close to the typical Washington figure of 36 mg/L. Of the 10 nearest cities we track, 8 have softer water and 2 have harder. The range nearby runs from 13 mg/L in Mill Creek East to 43 in Silver Firs.

What 29 mg/L means at home

Soap and shampoo lather with very little product. Kettles and showerheads stay mostly free of white crust.

Some people notice that soap feels slow to rinse off in soft water. That slippery feel is normal and harmless.

Hardness is not a health problem, and EPA sets no limit for it. It is a matter of scale and soap.

What to do about it

Nothing, as far as hardness goes. At 29 mg/L a softener would have almost nothing to remove.

Carbon filter

If the water tastes of chlorine, a pitcher or faucet carbon filter takes care of that. It does not change hardness.

EPA record for Monroe's water system

Monroe Water System · PWSID WA5355820

No health-based violations since 2016

Serves about 23,467 people from surface water.

Health-based
0
Monitoring or reporting
3
Open now
0

EPA lists this system as serving Monroe.

Health-based means a contaminant above its legal limit or a missed treatment step. Monitoring and reporting violations are late or missing tests and notices. Source: EPA ECHO, 2026Q3 export, violations with periods starting 2016 or later. Full EPA record.

Questions

Is Monroe water hard?

No. It measures about 29 mg/L (1.7 grains per gallon), which the USGS classes as soft.

What is the water hardness in Monroe in grains per gallon?

About 1.7 gpg. One grain per gallon equals 17.1 mg/L, so 29 mg/L divided by 17.1 gives 1.7.

Has the Monroe water system had EPA violations?

EPA records show no health-based violations for Monroe Water System since 2016. There were also 3 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 145 cities in Washington

Hardness data: TapWaterData US Water Hardness (county estimate, July 4, 2026), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.