How hard is the water in Tualatin, OR?

Tap water hardness
77mg/L
4.5gpg
Moderately hardCounty estimate

County estimate from 999 water samples in Washington County · July 2026

OR typical
24 mg/L
EPA health violations since 2016
0
Softener for 3 people
24k grain
Data
County estimate

Water samples from around Tualatin put hardness at about 77 mg/L (4.5 gpg), which would be moderately hard on the USGS scale. Treat this as a rough guide: it is the median of 999 samples taken across Washington County, mostly wells and streams, not a test of Tualatin's treated tap water. One more reason for caution: EPA lists Tualatin's water system as using surface water, which is often softer than the wells behind the county figure.

Tualatin on the hardness scale, with nearby cities
060120180240300360+OR typical 24Tigard: 22 mg/LTigard 22Bull Mountain: 22 mg/LBull Mountain 22Garden Home-Whitford: 23 mg/LGarden Home-Whitford 23West Linn: 23 mg/LWest Linn 23Oak Grove: 23 mg/LOak Grove 23Wilsonville: 24 mg/LWilsonville 24Lake Oswego: 26 mg/LLake Oswego 26Beaverton: 35 mg/LBeaverton 35Raleigh Hills: 35 mg/LRaleigh Hills 35Sherwood: 77 mg/LSherwood 77Tualatin 77mg/L as calcium carbonate060120180240300360+OR 24Tigard: 22 mg/LTigard 22Bull Mountain: 22 mg/LBull Mount. 22Garden Home-Whitford: 23 mg/LGarden Hom. 23Wilsonville: 24 mg/LWilsonville 24Lake Oswego: 26 mg/LLake Oswego 26Sherwood: 77 mg/LSherwood 7777 mg/Lmg/L as calcium carbonate
Soft 0–60 mg/LModerately hard 61–120 mg/LHard 121–180 mg/LVery hard 181+ mg/L

Tualatin sits 53 mg/L above the typical Oregon figure of 24. None of the 10 nearest cities we track has harder water. The range nearby runs from 22 mg/L in Tigard to 77 in Sherwood.

What 77 mg/L means at home

You may see faint white spots on glasses and shower doors after the water dries.

Scale builds up slowly. A kettle or coffee maker needs descaling now and then, maybe every few months.

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

Optional. Plenty of households at this level live with it and descale the kettle now and then.

Water softener

Worth a look if spots on glass bother you, or if your tankless water heater manual asks for softer water.

Carbon filter

Improves taste and removes chlorine. It leaves calcium and magnesium in place.

Softener size for Tualatin

3 people × 75 gallons a day × 4.5 gpg = 1,012 grains a day. A 24,000-grain unit regenerates about every 23 days.

Size it for your household

EPA record for Tualatin's water system

Tualatin, City of · PWSID OR4100906

No health-based violations since 2016

Serves about 28,106 people from surface water.

Health-based
0
Monitoring or reporting
6
Open now
0

EPA lists this system as serving Tualatin.

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 Tualatin water hard?

Somewhat. It measures about 77 mg/L (4.5 grains per gallon), which the USGS classes as moderately hard.

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

About 4.5 gpg. One grain per gallon equals 17.1 mg/L, so 77 mg/L divided by 17.1 gives 4.5.

What size water softener do I need in Tualatin?

For 3 people using 75 gallons each per day, 4.5 gpg works out to about 1,012 grains a day. A 24,000-grain softener covers that with a regeneration about every 23 days.

Has the Tualatin water system had EPA violations?

EPA records show no health-based violations for Tualatin, City of since 2016. There were also 6 monitoring or reporting violations, which are about late or missing tests and notices.

Nearby cities

All 53 cities in Oregon

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.