Water Quality in Sioux Falls, SD

Sioux Falls's water has very hard water (250 PPM). A water softener is recommended to protect plumbing and appliances. Read below for a full breakdown.

City of Sioux Falls · Source: Big Sioux River + wells · Serves 192,517 residents

250
Hardness (PPM)
410
TDS (PPM)
0.8
Chlorine (mg/L)
3
PFAS (ppt)
2
Lead (ppb)
250 PPM 0 400 Very Hard
CONTAMINANT LEVELS Hardness 250 PPM TDS 410 PPM PFAS 3 ppt Lead 2 ppb Chlorine 0.8 mg/L Nitrate 3 mg/L

Hardness Scale: Where Sioux Falls Falls

Soft 060120180250400+
Very hard waterHigh TDSAgricultural runoff

What Sioux Falls's Water Means for Your Home

Sioux Falls residents deal with some of the hardest municipal water in the country. At 250 PPM (undefined grains per gallon), the water contains high concentrations of dissolved calcium and magnesium picked up from the regional geology as surface water is treated and distributed. This is not a safety issue. The minerals are safe to consume. But they create real, measurable costs for homeowners. Hard water at 250 PPM costs the average household $800 to $1,200 per year in hidden expenses, including higher energy bills from scale-insulated water heaters, increased soap and detergent usage, and premature appliance failure. Many Sioux Falls homeowners discover this only after a water heater replacement or plumber visit.

Beyond hardness, Sioux Falls's water quality is generally within EPA guidelines for regulated contaminants. Chlorine is present at 0.8 mg/L as a disinfectant residual, which is normal for municipal water systems. If you notice a pool-like taste or experience dry skin, a whole-house carbon filter is the most common and affordable solution. For homeowners who want to understand the full picture, requesting your utility's annual Consumer Confidence Report provides neighborhood-level data.

ContaminantDetectedHealth GuidelineLegal LimitStatus
Hardness (as CaCO₃)250 PPM< 60 PPMNo federal limit⚠ Very Hard
Total Dissolved Solids410 PPM< 300 PPM500 PPM⚠ Elevated
PFAS (total)3 ppt4 ppt (EPA)4 ppt (2024)✓ OK
Lead2 ppb0 ppb (no safe level)15 ppb (action level)✓ Low
Chlorine / Chloramine0.8 mg/LTaste threshold ~1.04.0 mg/L✓ Normal
Nitrate3 mg/L5 mg/L10 mg/L✓ OK

Recommendations for Sioux Falls Homes

🧂 Water Softener
At 250 PPM (undefined GPG), Sioux Falls's water is very hard. Scale will accumulate in pipes, water heaters, and on fixtures. A salt-based ion exchange softener removes the calcium and magnesium causing the problem. For a typical Sioux Falls household of 2 to 4 people, a 48,000-grain softener is the right starting size.
Learn more about this solution →

About Sioux Falls's Water Supply

Water Utility: City of Sioux Falls

Water Source: Big Sioux River + wells

Population Served: 192,517

Hardness: 250 PPM (undefined grains per gallon)

Water quality can vary by neighborhood and season. The values above represent typical averages reported by City of Sioux Falls. To get exact numbers for your address, request a copy of the most recent Consumer Confidence Report (CCR) from your utility, or have your water independently tested.

Compare Sioux Falls to Other South Dakota Cities

Rapid City

221 PPM · Very Hard

Aberdeen

204 PPM · Very Hard

Frequently Asked Questions About Sioux Falls Water

Is Sioux Falls tap water safe to drink?
Sioux Falls's water meets EPA legal standards for drinking water safety. However, legal limits and health-optimal levels are different things. Review the contaminant table above for specific numbers and how they compare to both legal limits and health guidelines.
Do I need a water softener in Sioux Falls?
Yes. At 250 PPM (undefined GPG), Sioux Falls's water is very hard. Without a softener, expect visible scale buildup on faucets and shower heads, reduced water heater efficiency (15 to 25 percent higher energy costs), spotted dishes and glassware, and soap that does not lather well. A salt-based water softener is the standard solution. For a typical Sioux Falls home with 2 to 4 residents, a 48,000-grain system is the most common starting size.
What water filter is best for Sioux Falls?
The best filter depends on which contaminants you want to address. See our softener vs. filter guide to understand the difference between these categories.
Where does Sioux Falls's water come from?
Sioux Falls's drinking water is sourced from Big Sioux River + wells and treated by City of Sioux Falls.
What is the hardness of Sioux Falls water in grains per gallon?
Sioux Falls's water hardness is undefined grains per gallon (GPG), which equals 250 parts per million (PPM). This is classified as very hard. Most water softener manufacturers recommend treatment above 7 GPG. To convert: 1 GPG = 17.1 PPM.
Does Sioux Falls water damage tankless water heaters?
Yes. Most tankless water heater manufacturers recommend water hardness below 7 to 11 GPG (120 to 188 PPM). At undefined GPG, Sioux Falls's water exceeds this threshold. Scale buildup inside the heat exchanger reduces efficiency and can void the manufacturer's warranty. A water softener installed upstream of the tankless heater is the standard solution.
Is Sioux Falls water safe for babies and infants?
Sioux Falls's water meets all EPA safety standards and is generally considered safe for preparing infant formula. The hardness minerals (calcium and magnesium) are not harmful. If your home has older plumbing, running cold water for 30 seconds before use is a good precaution to flush any lead from pipes.
How much does hard water cost a Sioux Falls household per year?
At 250 PPM, hard water costs the average Sioux Falls household an estimated $800 to $1,200 per year in hidden costs. This includes 15 to 25 percent higher water heating bills from scale insulation, 50 to 75 percent more soap and detergent usage, shorter appliance lifespans (water heaters, dishwashers, washing machines), and increased plumbing maintenance. A water softener typically costs $600 to $1,500 installed and $50 to $100 per year in salt, which means most Sioux Falls households see a return on investment within 1 to 2 years.

Data sources. Water quality data compiled from EPA SDWIS, EWG Tap Water Database, USGS water hardness studies, and the City of Sioux Falls Consumer Confidence Report. Hardness and contaminant levels represent typical average values and may vary by neighborhood and season. Last updated: 2026-02-12.