Bryn Mawr-Skyway, WA water hardness

Tap water hardness
35mg/L
2.0gpg
SoftReports range 35–53

Reported by Seattle Public Utilities · October 2025

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

Bryn Mawr-Skyway water measures 35 mg/L (2.0 gpg) of hardness, soft by USGS standards. The number comes from Seattle Public Utilities, dated October 2025. Reports for this system disagree, with values from 35 to 53 mg/L.

Bryn Mawr-Skyway on the hardness scale, with nearby cities
060120180240300360+WA typical 36Newcastle: 27 mg/LNewcastle 27East Renton Highlands: 30 mg/LEast Renton Highlands 30White Center: 31 mg/LWhite Center 31Burien: 33 mg/LBurien 33Tukwila: 37 mg/LTukwila 37Mercer Island: 39 mg/LMercer Island 39Renton: 49 mg/LRenton 49Fairwood: 53 mg/LFairwood 53SeaTac: 64 mg/LSeaTac 64Normandy Park: 64 mg/LNormandy Park 64Bryn Mawr-Skyway 35mg/L as calcium carbonate060120180240300360+WA 36Newcastle: 27 mg/LNewcastle 27Burien: 33 mg/LBurien 33Tukwila: 37 mg/LTukwila 37Mercer Island: 39 mg/LMercer Isl. 39Renton: 49 mg/LRenton 49SeaTac: 64 mg/LSeaTac 6435 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Bryn Mawr-Skyway sits close to the typical Washington figure of 36 mg/L. Of the 10 nearest cities we track, 4 have softer water and 6 have harder. The range nearby runs from 27 mg/L in Newcastle to 64 in SeaTac.

What 35 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 35 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 Bryn Mawr-Skyway's water system

Seattle Public Utilities · PWSID WA5377050

No health-based violations since 2016

Serves about 1,161,961 people from surface water.

Health-based
0
Monitoring or reporting
0
Open now
0

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

No. It measures about 35 mg/L (2.0 grains per gallon), which the USGS classes as soft.

What is the water hardness in Bryn Mawr-Skyway in grains per gallon?

About 2.0 gpg. One grain per gallon equals 17.1 mg/L, so 35 mg/L divided by 17.1 gives 2.0.

Has the Bryn Mawr-Skyway water system had EPA violations?

EPA records show no health-based violations for Seattle Public Utilities since 2016.

Nearby cities

All 145 cities in Washington

Hardness data: TapWaterData US Water Hardness (utility report, October 12, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.