Federal Way, WA water hardness

Tap water hardness
31mg/L
1.8gpg
Soft

Reported by Tacoma Water Division City of · September 2025

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

Tap water in Federal Way has about 31 mg/L of hardness, which is 1.8 grains per gallon. On the USGS scale that counts as soft. The number comes from Tacoma Water Division City of, dated September 2025.

Federal Way on the hardness scale, with nearby cities
060120180240300360+WA typical 36Tacoma: 22 mg/LTacoma 22Waller: 22 mg/LWaller 22Lakeland South: 38 mg/LLakeland South 38Milton: 38 mg/LMilton 38Pacific: 39 mg/LPacific 39Lakeland North: 48 mg/LLakeland North 48Des Moines: 48 mg/LDes Moines 48Kent: 52 mg/LKent 52Auburn: 58 mg/LAuburn 58Normandy Park: 64 mg/LNormandy Park 64Federal Way 31mg/L as calcium carbonate060120180240300360+WA 36Lakeland South: 38 mg/LLakeland S. 38Milton: 38 mg/LMilton 38Pacific: 39 mg/LPacific 39Lakeland North: 48 mg/LLakeland N. 48Des Moines: 48 mg/LDes Moines 48Auburn: 58 mg/LAuburn 5831 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Federal Way sits close to the typical Washington figure of 36 mg/L. Of the 10 nearest cities we track, 2 have softer water and 8 have harder. The range nearby runs from 22 mg/L in Tacoma to 64 in Normandy Park.

What 31 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 31 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 Federal Way's water system

Tacoma Water Division City of · PWSID WA5386800

No health-based violations since 2016

Serves about 446,245 people from surface water.

Health-based
0
Monitoring or reporting
0
Open now
0

TapWaterData ties Federal Way to this system. EPA's service-area records do not name Federal Way, 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 Federal Way water hard?

No. It measures about 31 mg/L (1.8 grains per gallon), which the USGS classes as soft.

What is the water hardness in Federal Way in grains per gallon?

About 1.8 gpg. One grain per gallon equals 17.1 mg/L, so 31 mg/L divided by 17.1 gives 1.8.

Has the Federal Way water system had EPA violations?

EPA records show no health-based violations for Tacoma Water Division City of since 2016.

Nearby cities

All 145 cities in Washington

Hardness data: TapWaterData US Water Hardness (utility report, September 22, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.