Des Moines, WA water hardness

Tap water hardness
48mg/L
2.8gpg
SoftReports range 48–84

Reported by Lakehaven Water and Sewer District · June 2025

WA typical
36 mg/L
EPA health violations since 2016
0
Data
Utility report

Des Moines water measures 48 mg/L (2.8 gpg) of hardness, soft by USGS standards. The number comes from Lakehaven Water and Sewer District, dated June 2025. Reports for this system disagree, with values from 48 to 84 mg/L.

Des Moines on the hardness scale, with nearby cities
060120180240300360+WA typical 36Federal Way: 31 mg/LFederal Way 31Burien: 33 mg/LBurien 33Bryn Mawr-Skyway: 35 mg/LBryn Mawr-Skyway 35Tukwila: 37 mg/LTukwila 37Lakeland South: 38 mg/LLakeland South 38Lakeland North: 48 mg/LLakeland North 48Kent: 52 mg/LKent 52Auburn: 58 mg/LAuburn 58Normandy Park: 64 mg/LNormandy Park 64SeaTac: 64 mg/LSeaTac 64Des Moines 48mg/L as calcium carbonate060120180240300360+WA 36Federal Way: 31 mg/LFederal Way 31Burien: 33 mg/LBurien 33Lakeland North: 48 mg/LLakeland N. 48Kent: 52 mg/LKent 52Normandy Park: 64 mg/LNormandy P. 64SeaTac: 64 mg/LSeaTac 6448 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Des Moines sits 12 mg/L above the typical Washington figure of 36. Of the 10 nearest cities we track, 5 have softer water and 4 have harder. The range nearby runs from 31 mg/L in Federal Way to 64 in Normandy Park.

What 48 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 48 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 Des Moines's water system

Lakehaven Water and Sewer District · PWSID WA5341997

No health-based violations since 2016

Serves about 148,809 people from surface water.

Health-based
0
Monitoring or reporting
1
Open now
0

TapWaterData ties Des Moines to this system. EPA's service-area records do not name Des Moines, so check the utility printed on your water bill.

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 Des Moines water hard?

No. It measures about 48 mg/L (2.8 grains per gallon), which the USGS classes as soft.

What is the water hardness in Des Moines in grains per gallon?

About 2.8 gpg. One grain per gallon equals 17.1 mg/L, so 48 mg/L divided by 17.1 gives 2.8.

Has the Des Moines water system had EPA violations?

EPA records show no health-based violations for Lakehaven Water and Sewer District since 2016. There were also 1 monitoring or reporting violation, which are about late or missing tests and notices.

Nearby cities

All 145 cities in Washington

Hardness data: TapWaterData US Water Hardness (utility report, June 9, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.