Sioux City, IA: 9 Violations — 66/100 (2026)
9 ZIP codes · 3 water systems · Updated 2026-06-03
Sioux City lands near the IA median for water safety — compliance results are mixed, and the city's middle-grade standing reflects genuine variability across service areas rather than one problem driving the whole picture.
How Sioux City Compares
Data: EPA SDWIS Last verified: 2026-06-03
Water Quality Map: Sioux City, IA
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Score Distribution
Safety grade breakdown for Sioux City's 9 ZIP codes.
Key Facts for Sioux City Residents
- Your city's water systems recorded 9 violations in the past 5 years.
- Average lead level: 0.002 mg/L.
- Homes built before 1986: 84% — older plumbing may contain lead solder.
- Estimated remediation: $2,933 per household.
- CDC health risk index: 13.32 — above typical levels.
Sioux City's Water Providers
Multiple utilities divide Sioux City, IA's water service — 3 leading providers among 3 on the federal register.
Overview
We track water quality and home safety data for 9 ZIP codes in Sioux City, Iowa, covering 3 community water systems serving approximately 89,537 people.
9 of 9 ZIP codes (100%) have recorded EPA violations. All violations are monitoring/reporting type.
Home Safety Score
Average Home Safety Score for Sioux City: C (66/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Sioux City water systems draw from: Groundwater, Surface water.
Lead & Copper
- Average lead level (90th percentile): 0.0020 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 1 (High Risk)
- Zone 1 (High): 9 ZIP codes
- Zone 2 (Moderate): 0 ZIP codes
- Zone 3 (Low): 0 ZIP codes
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 10 | 9 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 51101 | B | 1 | 0 | Sioux City Water Supply |
| 51102 | B | 1 | 0 | Sioux City Water Supply |
| 51103 | C | 1 | 0 | Sioux City Water Supply |
| 51104 | C | 1 | 0 | Sioux City Water Supply |
| 51105 | B | 1 | 0 | Sioux City Water Supply |
| 51106 | C | 1 | 0 | Sioux City Water Supply |
| 51108 | B | 1 | 0 | Sioux City Water Supply |
| 51109 | C | 1 | 0 | Sioux City Water Supply |
| 51111 | C | 1 | 0 | Sioux City Water Supply |
All ZIP Codes in Sioux City
- 51101 [B] — 1 violation
- 51102 [B] — 1 violation
- 51103 [C] — 1 violation
- 51104 [C] — 1 violation
- 51105 [B] — 1 violation
- 51106 [C] — 1 violation
- 51108 [B] — 1 violation
- 51109 [C] — 1 violation
- 51111 [C] — 1 violation
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
Updated daily.
Sioux City Community Health Snapshot
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
What's in Sioux City's Water?
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
Sioux City Infrastructure Age
With 84% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
The character of Sioux City's housing stock is one of deep historical layering — a median build year of 1943 signals a city built largely before the plumbing era changes of 1986 and 1970. Lead-soldered copper joints and, in the oldest properties, lead service lines are commonly present in this inventory. That context shapes what individual water testing may reveal, particularly in neighborhoods where the oldest housing is concentrated.
Over half of homes in Sioux City were built before 1986, when lead solder was banned. Older plumbing may leach lead into drinking water, especially with corrosive water chemistry.
Source: U.S. Census Bureau ACS B25034.
How Remediation Costs Compare in Sioux City
Property value and cost data for Sioux City produce a moderate remediation-share classification — a level where advance financial planning has real practical value and the commitment is realistic for most homeowners who approach it deliberately.
Remediation costs are moderate relative to home values in Sioux City. The estimated $1,956–$3,967 range is manageable for most homeowners but still worth budgeting for. Home values are 1% above the Iowa average.
Sioux City: Lead Risk & Vulnerable Populations
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
84% — that captures the slice of Sioux City housing dating from before the federal ban on solder containing lead. It pairs with aggregate utility readings that either approach or cross 0.015 mg/L, the benchmark set under the EPA Lead and Copper Rule. Together, the two figures shift one-home reads into a standard household-level confirmation, particularly for families with kids. A certified lead-removal filter is available through retailer-verified channels if a kit returns results that warrant additional measures.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Sioux City: Flood History & Water Damage Risk
The NFIP claim record for Sioux City — 246 filed incidents — reflects genuine, recurring flood exposure rather than an isolated event or two. When a community accumulates flood claims at this volume and carries 78% of its ZIP codes inside FEMA-designated zones, flood history starts to factor into water quality planning in ways it doesn't for lower-exposure areas. Flooding introduces specific contamination pathways — runoff overwhelming treatment facility intake, surface water infiltrating private wells, and pressure disruptions in distribution systems allowing backflow — all of which become more relevant as flood frequency increases.
Sioux City has a moderate flood history with 246 FEMA claims averaging $7,750 per payout. 78% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$2,933</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
What You Can Do in Sioux City
- Test your water at home. City-level data shows averages — your tap may differ. NSF-certified test kits cost $20-40 and give results in days.
- Install a certified water filter. Filters rated for Haloacetic Acids (HAA5) can reduce the most common contaminant found in Sioux City's water.
- Check your home's plumbing. With 84% of homes built before 1986, lead solder is a real possibility.
Deep Dive Reports
Detailed analysis for Sioux City, IA