Hard water in Ottawa, KS
Reported by Ottawa, City of · June 2022
- KS typical
- 138 mg/L
- EPA health violations since 2016
- 3
- Softener for 3 people
- 24k grain
- Data
- Utility report
Ottawa water measures 144 mg/L (8.4 gpg) of hardness, hard by USGS standards. The number comes from Ottawa, City of, dated June 2022.
Ottawa sits close to the typical Kansas figure of 138 mg/L. Of the 10 nearest cities we track, 9 have softer water and 1 has harder. The range nearby runs from 133 mg/L in Paola to 215 in Tonganoxie.
What 144 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 144 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 × 8.4 gpg = 1,899 grains a day. A 24,000-grain unit regenerates about every 12 days.
EPA record for Ottawa's water system
3 health-based violations since 2016
Serves about 12,604 people from surface water.
- Health-based
- 3
- Monitoring or reporting
- 2
- Open now
- 0
| Contaminant or rule | Violations | Period | Status |
|---|---|---|---|
| Haloacetic acids (HAA5)a disinfection byproduct | 3 | 2019–2024 | 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 Ottawa water hard?
Yes. It measures about 144 mg/L (8.4 grains per gallon), which the USGS classes as hard.
What is the water hardness in Ottawa in grains per gallon?
About 8.4 gpg. One grain per gallon equals 17.1 mg/L, so 144 mg/L divided by 17.1 gives 8.4.
What size water softener do I need in Ottawa?
For 3 people using 75 gallons each per day, 8.4 gpg works out to about 1,899 grains a day. A 24,000-grain softener covers that with a regeneration about every 12 days.
Has the Ottawa water system had EPA violations?
EPA records show 3 health-based violations for Ottawa, City of since 2016, involving Haloacetic acids (HAA5). There were also 2 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Paola133 mg/LHard
- Gardner135 mg/LHard
- Lawrence142 mg/LHard
- Spring Hill135 mg/LHard
- De Soto135 mg/LHard
- Olathe140 mg/LHard
- Louisburg133 mg/LHard
- Lenexa135 mg/LHard
- Tonganoxie215 mg/LVery hard
- Overland Park135 mg/LHard
Hardness data: TapWaterData US Water Hardness (utility report, June 13, 2022), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.