Hard water in Owasso, OK
Reported by Washington CO RWD #3 (New,#1) · January 2025
- OK typical
- 152 mg/L
- EPA health violations since 2016
- 1
- Softener for 3 people
- 24k grain
- Data
- Utility report
Owasso water measures 153 mg/L (8.9 gpg) of hardness, hard by USGS standards. The number comes from Washington CO RWD #3 (New,#1), dated January 2025.
Owasso sits close to the typical Oklahoma figure of 152 mg/L. None of the 10 nearest cities we track has harder water. The range nearby runs from 92 mg/L in Catoosa to 153 in Collinsville.
What 153 mg/L means at home
Expect white crust on faucets and showerheads, plus spots on dishes that come out of the dishwasher.
Kettles collect scale quickly. Water heaters build up sediment at the bottom of the tank, which makes them work harder over time.
Soap and detergent need a little more to lather, and soap scum shows up in the tub.
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
At 153 mg/L most of the trouble is scale, and only a few things deal with it.
Ion-exchange water softener
The standard whole-house fix. It swaps calcium and magnesium for sodium or potassium and needs salt plus a drain. Size it with the calculator below.
Salt-free conditioner
No salt and no drain line. It changes how minerals form scale instead of removing them, so water still tests hard.
Reverse osmosis or carbon filter
Under-sink reverse osmosis removes minerals from drinking water only. Plain carbon filters improve taste but do not soften.
3 people × 75 gallons a day × 8.9 gpg = 2,014 grains a day. A 24,000-grain unit regenerates about every 11 days.
EPA record for Owasso's water system
1 health-based violation since 2016
Serves about 23,000 people from surface water.
- Health-based
- 1
- Monitoring or reporting
- 2
- Open now
- 0
EPA lists Owasso as the system serving Owasso. The hardness figure above comes from a different system's report, which TapWaterData uses for Owasso.
| Contaminant or rule | Violations | Period | Status |
|---|---|---|---|
| Lead and Copper Rulecorrosion control and lead sampling | 1 | 2024 | Resolved |
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 Owasso water hard?
Yes. It measures about 153 mg/L (8.9 grains per gallon), which the USGS classes as hard.
What is the water hardness in Owasso in grains per gallon?
About 8.9 gpg. One grain per gallon equals 17.1 mg/L, so 153 mg/L divided by 17.1 gives 8.9.
What size water softener do I need in Owasso?
For 3 people using 75 gallons each per day, 8.9 gpg works out to about 2,014 grains a day. A 24,000-grain softener covers that with a regeneration about every 11 days.
Has the Owasso water system had EPA violations?
EPA records show 1 health-based violation for Owasso since 2016, involving Lead and Copper Rule. There were also 2 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Collinsville153 mg/LHard
- Skiatook153 mg/LHard
- Catoosa92 mg/LModerately hard
- Tulsa110 mg/LModerately hard
- Claremore131 mg/LHard
- Broken Arrow92 mg/LModerately hard
- Sand Springs111 mg/LModerately hard
- Jenks148 mg/LHard
- Bixby92 mg/LModerately hard
- Coweta92 mg/LModerately hard
Hardness data: TapWaterData US Water Hardness (utility report, January 27, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.