Walla Walla, WA water hardness

Tap water hardness
39mg/L
2.3gpg
SoftCounty estimate

County estimate from 21 water samples in Walla Walla County · July 2026

WA typical
36 mg/L
EPA health violations since 2016
36
Data
County estimate

Water samples from around Walla Walla put hardness at about 39 mg/L (2.3 gpg), which would be soft on the USGS scale. Treat this as a rough guide: it is the median of 21 samples taken across Walla Walla County, mostly wells and streams, not a test of Walla Walla's treated tap water. One more reason for caution: EPA lists Walla Walla's water system as using surface water, which is often softer than the wells behind the county figure.

Walla Walla on the hardness scale, with nearby cities
060120180240300360+WA typical 36West Richland: 33 mg/LWest Richland 33Othello: 33 mg/LOthello 33Toppenish: 63 mg/LToppenish 63Richland: 89 mg/LRichland 89Finley: 96 mg/LFinley 96Kennewick: 96 mg/LKennewick 96Pullman: 115 mg/LPullman 115Moses Lake: 168 mg/LMoses Lake 168Grandview: 208 mg/LGrandview 208Pasco: 268 mg/LPasco 268Walla Walla 39mg/L as calcium carbonate060120180240300360+WA 36West Richland: 33 mg/LWest Richl. 33Othello: 33 mg/LOthello 33Richland: 89 mg/LRichland 89Finley: 96 mg/LFinley 96Kennewick: 96 mg/LKennewick 96Pasco: 268 mg/LPasco 26839 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Walla Walla 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 33 mg/L in West Richland to 268 in Pasco.

What 39 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 39 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 Walla Walla's water system

Walla Walla Water Division · PWSID WA5392500

36 health-based violations since 2016

Serves about 42,959 people from surface water.

Health-based
36
Monitoring or reporting
18
Open now
0

EPA lists this system as serving Walla Walla.

20162017201820192020202120222023202420252026Surface Water Treatment Rule (LT2)Surface Water Treatment Rule'16'18'20'22'24'26Surface Water Treatment Rule (LT2)Surface Water Treatment Rule
Each dot is one health-based violation, placed at the start of its compliance period.
Contaminant or ruleViolationsPeriodStatus
Surface Water Treatment Rule (LT2)filtration and disinfection122018Resolved
Surface Water Treatment Rulefiltration and disinfection242016–2017Resolved

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 Walla Walla water hard?

No. It measures about 39 mg/L (2.3 grains per gallon), which the USGS classes as soft.

What is the water hardness in Walla Walla in grains per gallon?

About 2.3 gpg. One grain per gallon equals 17.1 mg/L, so 39 mg/L divided by 17.1 gives 2.3.

Has the Walla Walla water system had EPA violations?

EPA records show 36 health-based violations for Walla Walla Water Division since 2016, involving Surface Water Treatment Rule (LT2), Surface Water Treatment Rule. There were also 18 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 (county estimate, July 4, 2026), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.