Maple Valley, WA water hardness

Tap water hardness
46mg/L
2.7gpg
Soft

Reported by Covington Water District · October 2025

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

Maple Valley water measures 46 mg/L (2.7 gpg) of hardness, soft by USGS standards. The number comes from Covington Water District, dated October 2025.

Maple Valley on the hardness scale, with nearby cities
060120180240300360+WA typical 36East Renton Highlands: 30 mg/LEast Renton Highlands 30Black Diamond: 46 mg/LBlack Diamond 46Renton: 49 mg/LRenton 49Lake Morton-Berrydale: 52 mg/LLake Morton-Berrydale 52Kent: 52 mg/LKent 52Fairwood: 53 mg/LFairwood 53Auburn: 58 mg/LAuburn 58Covington: 59 mg/LCovington 59Enumclaw: 62 mg/LEnumclaw 62Lake Tapps: 95 mg/LLake Tapps 95Maple Valley 46mg/L as calcium carbonate060120180240300360+WA 36East Renton Highlands: 30 mg/LEast Rento. 30Black Diamond: 46 mg/LBlack Diam. 46Lake Morton-Berrydale: 52 mg/LLake Morto. 52Kent: 52 mg/LKent 52Fairwood: 53 mg/LFairwood 53Covington: 59 mg/LCovington 5946 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Maple Valley sits close to the typical Washington figure of 36 mg/L. Of the 10 nearest cities we track, 1 has softer water and 8 have harder. The range nearby runs from 30 mg/L in East Renton Highlands to 95 in Lake Tapps.

What 46 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 46 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 Maple Valley's water system

Covington Water District · PWSID WA5341650

No health-based violations since 2016

Serves about 56,172 people from surface water.

Health-based
0
Monitoring or reporting
0
Open now
0

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

No. It measures about 46 mg/L (2.7 grains per gallon), which the USGS classes as soft.

What is the water hardness in Maple Valley in grains per gallon?

About 2.7 gpg. One grain per gallon equals 17.1 mg/L, so 46 mg/L divided by 17.1 gives 2.7.

Has the Maple Valley water system had EPA violations?

EPA records show no health-based violations for Covington Water District since 2016.

Nearby cities

All 145 cities in Washington

Hardness data: TapWaterData US Water Hardness (utility report, October 8, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.