Water Quality in North Sioux City, SD: No Violations — Grade C
Grade C · Score 55/100 · 1 water system · Updated 2026-05-03
North Sioux City'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
No EPA violations have been identified for North Sioux City, SD — 1 system, all within federal limits.
Water Quality by ZIP Code in North Sioux City
Water quality varies across North Sioux City's 1 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 57049 | C | 55 | 0 | 0 | View report → |
Water Quality Overview
North Sioux City, South Dakota receives a water quality grade of C with an overall score of 55 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
No EPA violations have been recorded for the 1 water system serving North Sioux City. This is a positive indicator, though it does not guarantee the absence of all contaminants — some substances (like PFAS) are not yet fully regulated.
What Grade C Means
A grade of C indicates moderate compliance issues. North Sioux City'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 North Sioux City water systems is 0.0040 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
Radon Risk
North Sioux City 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 North Sioux City
North Sioux City is served by 1 community water system regulated under the Safe Drinking Water Act. These systems collectively serve approximately 3,042 people across 1 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
How to Check Your Water in North Sioux City
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
North Sioux City vs. Nearby South Dakota Cities
How North Sioux City's water quality compares to similar cities in South Dakota:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| North Sioux City | C | 0 | 1 | 3,042 |
| Piedmont | B | 4 | 5 | 3,054 |
| Canton | C | 0 | 1 | 3,066 |
| Emery | C | 0 | 2 | 3,165 |
Common Questions About North Sioux City Water
These are the most common questions residents search for about water quality in North Sioux City, South Dakota:
Is North Sioux City water hard or soft? Water hardness varies by source. North Sioux City's 1 water system uses a single source. Check your ZIP code report for specific hardness data.
Can I drink North Sioux City tap water? North Sioux City's water receives a grade of C (55/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for North Sioux City? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
North Sioux City vs. South Dakota Average
Understanding how North Sioux City 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 North Sioux City.
ZIP Codes in North Sioux City
North Sioux City spans 1 ZIP code. 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.