How hard is the water in Sioux Falls, SD?
Reported by Sioux Falls · August 2024
- SD typical
- 124 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- Utility report
Sioux Falls water measures 119 mg/L (7.0 gpg) of hardness, moderately hard by USGS standards. The number comes from Sioux Falls, dated August 2024.
At 119 mg/L, Sioux Falls is close to the typical South Dakota figure of 124 mg/L. None of the 3 nearest cities we track has softer water. The range nearby runs from 124 mg/L in Rapid City to 500 in Brookings.
What 119 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.
3 people × 75 gallons a day × 7.0 gpg = 1,566 grains a day. A 24,000-grain unit regenerates about every 15 days.
EPA record for Sioux Falls's water system
No health-based violations since 2016
Serves about 216,462 people from surface water.
- Health-based
- 0
- Monitoring or reporting
- 0
- Open now
- 0
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 Sioux Falls water hard?
Somewhat. It measures about 119 mg/L (7.0 grains per gallon), which the USGS classes as moderately hard.
What is the water hardness in Sioux Falls in grains per gallon?
About 7.0 gpg. One grain per gallon equals 17.1 mg/L, so 119 mg/L divided by 17.1 gives 7.0.
What size water softener do I need in Sioux Falls?
For 3 people using 75 gallons each per day, 7.0 gpg works out to about 1,566 grains a day. A 24,000-grain softener covers that with a regeneration about every 15 days.
Has the Sioux Falls water system had EPA violations?
EPA records show no health-based violations for Sioux Falls since 2016.
Nearby cities
Hardness data: TapWaterData US Water Hardness (utility report, August 12, 2024), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.