East Renton Highlands, WA water hardness

Tap water hardness
30mg/L
1.8gpg
Soft

Reported by King County Water District No 90 · October 2025

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

Tap water in East Renton Highlands has about 30 mg/L of hardness, which is 1.8 grains per gallon. On the USGS scale that counts as soft. The number comes from King County Water District No 90, dated October 2025.

East Renton Highlands on the hardness scale, with nearby cities
060120180240300360+WA typical 36Newcastle: 27 mg/LNewcastle 27Bryn Mawr-Skyway: 35 mg/LBryn Mawr-Skyway 35Tukwila: 37 mg/LTukwila 37Issaquah: 41 mg/LIssaquah 41Maple Valley: 46 mg/LMaple Valley 46Renton: 49 mg/LRenton 49Kent: 52 mg/LKent 52Fairwood: 53 mg/LFairwood 53Covington: 59 mg/LCovington 59Sammamish: 62 mg/LSammamish 62East Renton Highlands 30mg/L as calcium carbonate060120180240300360+WA 36Newcastle: 27 mg/LNewcastle 27Bryn Mawr-Skyway: 35 mg/LBryn Mawr-. 35Issaquah: 41 mg/LIssaquah 41Renton: 49 mg/LRenton 49Fairwood: 53 mg/LFairwood 53Covington: 59 mg/LCovington 5930 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

East Renton Highlands sits close to the typical Washington figure of 36 mg/L. Of the 10 nearest cities we track, 1 has softer water and 9 have harder. The range nearby runs from 27 mg/L in Newcastle to 62 in Sammamish.

What 30 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 30 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 East Renton Highlands's water system

King County Water District No 90 · PWSID WA5341150

No health-based violations since 2016

Serves about 20,100 people from surface water.

Health-based
0
Monitoring or reporting
2
Open now
0

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

No. It measures about 30 mg/L (1.8 grains per gallon), which the USGS classes as soft.

What is the water hardness in East Renton Highlands in grains per gallon?

About 1.8 gpg. One grain per gallon equals 17.1 mg/L, so 30 mg/L divided by 17.1 gives 1.8.

Has the East Renton Highlands water system had EPA violations?

EPA records show no health-based violations for King County Water District No 90 since 2016. There were also 2 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 (utility report, October 7, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.