Water Quality in Sioux Falls, SD: 40 Violations — Grade C
Grade C · Score 61/100 · 5 water systems · Updated 2026-05-03
Sioux Falls's water has moderate compliance issues. Residents in affected areas should consider filtration.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
Tracked under the EPA Safe Drinking Water program, Sioux Falls, SD shows 40 water violations on file — findings that span multiple violation categories and are detailed system by system in the data grid further down the page.
Water Quality Map: Sioux Falls, SD
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Water Quality by ZIP Code in Sioux Falls
Water quality varies across Sioux Falls's 20 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 57104 | C | 56 | 2 | 1 | View report → |
| 57105 | C | 56 | 2 | 1 | View report → |
| 57103 | C | 61 | 2 | 1 | View report → |
| 57106 | C | 61 | 2 | 1 | View report → |
| 57107 | C | 61 | 2 | 1 | View report → |
| 57108 | C | 61 | 2 | 1 | View report → |
| 57109 | C | 61 | 2 | 1 | View report → |
| 57117 | C | 61 | 2 | 1 | View report → |
| 57118 | C | 61 | 2 | 1 | View report → |
| 57186 | C | 61 | 2 | 1 | View report → |
| 57189 | C | 61 | 2 | 1 | View report → |
| 57192 | C | 61 | 2 | 1 | View report → |
| 57193 | C | 61 | 2 | 1 | View report → |
| 57194 | C | 61 | 2 | 1 | View report → |
| 57195 | C | 61 | 2 | 1 | View report → |
Violation Trend
EPA violations recorded for water systems serving Sioux Falls.
Water Quality Overview
Sioux Falls, South Dakota receives a water quality grade of C with an overall score of 61 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 5 water systems serving Sioux Falls have accumulated 40 EPA violations, including 20 health-based violations. These violations are tracked across 20 ZIP codes serving approximately 223,087 people.
What Grade C Means
A grade of C indicates moderate compliance issues. Sioux Falls's water systems have some violations that warrant attention. While the water may still be safe for most people, residents in affected ZIP codes should consider additional testing or filtration.
Lead Levels
The average 90th percentile lead level across Sioux Falls water systems is 0.0030 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 43% of homes built before 1986, Sioux Falls has a higher-than-average risk of lead from older plumbing. Lead solder was banned in 1986, and homes built before this date may have lead in pipes, solder joints, or fixtures.
Radon Risk
Sioux Falls is in EPA Radon Zone 1 (High risk). The EPA recommends all homes in Zone 1 areas be tested for radon. Radon is the second leading cause of lung cancer after smoking.
Water Systems Serving Sioux Falls
Sioux Falls is served by 5 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 223,087 people across 20 ZIP codes.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
The EPA has taken 140 enforcement actions against water systems serving Sioux Falls. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Sioux Falls
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels, violation history, and safety scores
Request your CCR — your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test — certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration — NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories — monitor your local utility website and local news for boil water advisories or system alerts
Contaminants Detected in Sioux Falls Water Systems
The following contaminants have been detected or caused violations across Sioux Falls's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Revised Total Coliform Rule | Microbiological | N/A | 20 | 20 | No |
| Chlorine residual | Disinfectant | 4 mg/L | 20 | 20 | Yes |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
Violation Trend Over Time
Year-by-year EPA violations recorded for water systems serving Sioux Falls:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2021 | 20 | 20 |
| 2025 | 20 | 20 |
Violation counts have remained stable over the observed period.
EPA Enforcement History
The EPA and state regulators have taken 7 enforcement actions against water systems serving Sioux Falls. Recent actions:
| Date | Action Type |
|---|---|
| 2025-07-07 | State Informal Action |
| 2025-06-16 | State Order Extension |
| 2024-10-25 | State Informal Action |
| 2024-07-24 | State Informal Enforcement |
| 2021-09-02 | State Informal Action |
| 2021-07-16 | State Informal Action |
| 2021-07-16 | State Order Extension |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-07-07.
Sioux Falls vs. Nearby South Dakota Cities
How Sioux Falls's water quality compares to similar cities in South Dakota:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Sioux Falls | C | 40 | 5 | 223,087 |
| Renner | D | 0 | 1 | 216,462 |
| Rapid City | B | 0 | 5 | 86,567 |
| Aberdeen | C | 16 | 5 | 50,402 |
Water Quality by ZIP Code in Sioux Falls
Water quality varies across Sioux Falls's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
| ZIP Code | Score | Grade | Violations | Health-Based |
|---|---|---|---|---|
| 57104 | 56 | C | 2 | 1 |
| 57105 | 56 | C | 2 | 1 |
| 57103 | 61 | C | 2 | 1 |
| 57106 | 61 | C | 2 | 1 |
| 57107 | 61 | C | 2 | 1 |
| 57108 | 61 | C | 2 | 1 |
| 57109 | 61 | C | 2 | 1 |
| 57117 | 61 | C | 2 | 1 |
| 57118 | 61 | C | 2 | 1 |
| 57186 | 61 | C | 2 | 1 |
| 57110 | 66 | C | 2 | 1 |
| 57101 | 66 | C | 2 | 1 |
| 57198 | 61 | C | 2 | 1 |
| 57197 | 61 | C | 2 | 1 |
| 57196 | 61 | C | 2 | 1 |
Common Questions About Sioux Falls Water
These are the most common questions residents search for about water quality in Sioux Falls, South Dakota:
Is Sioux Falls water hard or soft? Water hardness varies by source. Sioux Falls's 5 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Sioux Falls tap water? Sioux Falls's water receives a grade of C (61/100). There are 20 health-based violations — consider filtration.
What is the best water filter for Sioux Falls? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Sioux Falls vs. South Dakota Average
Understanding how Sioux Falls compares to the broader South Dakota average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below — water quality can vary significantly even within Sioux Falls.
ZIP Codes in Sioux Falls
Sioux Falls spans 20 ZIP codes. The ZIP with the lowest water quality score is 57101. Each ZIP code has its own water quality profile based on the specific water system serving that area. Check each ZIP code for detailed contaminant data, violation history, and system information.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Updated daily.