Home hazard report for 51103 — Sioux City, IA
ZIP 51103 is served by Sioux City Water Supply: 5 violations since 2016, latest lead result 2 ppb, PFAS 6 ppt. Woodbury County is in EPA radon zone 1.
Health-based violations since 2016: Epichlorohydrin, TTHM. All are listed as resolved.
90th-percentile lead in the latest round (Jan 2023). Lead comes mostly from household plumbing and service lines, so individual homes can be higher.
Highest PFOA or PFOS result in EPA’s 2023–2025 testing was at or above 4.0 ppt, EPA’s 2024 maximum contaminant level for each. 8 PFAS compounds detected.
Predicted average indoor radon above 4 pCi/L — EPA’s action level. Test your home.
FEMA’s overall natural-hazard risk for this census tract, relative to the rest of the U.S.
No active Superfund site within 10 miles of the ZIP center.
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Where ZIP 51103 is
Dashed: ZIP area · blue: utility service area · scroll or pinch to zoomDrinking water: Sioux City Water Supply
Health-based violations
| Contaminant or rule | Health-based violations since 2016 |
|---|---|
| Epichlorohydrin | 3 |
| TTHM | 2 |
A health-based violation means a contaminant exceeded its legal limit (MCL) or a required treatment technique was not met, as reported by the state to EPA’s SDWIS. All are listed as resolved or archived; the latest began Oct 2019.
Lead
90th-percentile lead per sampling round (90% of the homes sampled were at or below this level). Black line: EPA’s 15 ppb action level; under the Lead and Copper Rule Improvements the action level becomes 10 ppb from 2027.
PFAS (“forever chemicals”)
| Compound | Highest result | Samples with detection | EPA limit |
|---|---|---|---|
| PFHxS | 35 ppt | 4 of 8 | — |
| PFHxA | 33 ppt | 4 of 8 | — |
| PFPeA | 22 ppt | 4 of 8 | — |
| PFBS | 21 ppt | 4 of 8 | — |
| PFBA | 9.2 ppt | 4 of 8 | — |
| PFOA | 6 ppt | 2 of 8 | 4 ppt MCL |
| PFHpA | 4.8 ppt | 3 of 8 | — |
| PFOS | 4.3 ppt | 2 of 8 | 4 ppt MCL |
| PFDA | not detected | 0 of 8 | — |
| PFNA | not detected | 0 of 8 | — |
| HFPO-DA (GenX) | not detected | 0 of 8 | — |
EPA Fifth Unregulated Contaminant Monitoring Rule (UCMR 5), samples 2023–2025; ppt = parts per trillion (ng/L). The 4.0 ppt maximum contaminant levels for PFOA and PFOS were set by EPA in 2024; water systems have until the end of the decade to comply.
Radon in Woodbury County
EPA radon zone 1 — highest potential. Predicted average indoor radon above 4 pCi/L — EPA’s action level. Test your home.
Radon is a colorless, odorless radioactive gas from soil and rock, and the leading cause of lung cancer among non-smokers. EPA recommends fixing a home at 4 pCi/L or above and considering it from 2 pCi/L. A short-term test kit costs about $15–30. How radon zones work →
Natural hazard risk
FEMA rates the overall natural-hazard risk of this neighborhood (census tract) as Relatively Moderate, with very high social vulnerability and very high community resilience.
FEMA National Risk Index (December 2025): expected annual losses from each hazard combined with social vulnerability and community resilience, rated relative to all U.S. census tracts. Hazards not listed are not applicable here. It describes the area, not a single building; flood insurance maps (FEMA FIRMs) decide flood-insurance requirements.
Live conditions: river gauges and flood levels · tornado warnings · wildfire detections · earthquakes — our sister maps, updated from NOAA, USGS and NASA every few minutes.
Superfund sites nearby
No site on EPA’s Superfund National Priorities List lies within 10 miles of the center of this ZIP code.
EPA Superfund National Priorities List (NPL): the country’s most serious known hazardous-waste sites, each with an EPA cleanup record (linked). Distance is measured from the ZIP center to the site’s reference point; being near a site does not by itself mean exposure — EPA site pages describe what was found and how it is being cleaned up.
What this is — and isn’t. These are records your water utility and state reported to the EPA, and the EPA’s radon map for your county. They describe the system and the area, not the water from your own tap or the air in your home. For that, read your utility’s annual Consumer Confidence Report and test: lead and radon tests are inexpensive.
Questions about 51103
Who supplies drinking water to ZIP 51103?
Sioux City Water Supply (EPA ID IA9778054), a surface water (rivers, lakes) system serving about 85,791 people.
Is there lead in Sioux City, IA tap water?
The utility’s latest 90th-percentile lead result (Jan 2023) was 2 ppb; EPA’s action level is 15 ppb, falling to 10 ppb from 2027. Lead mostly comes from service lines and home plumbing, so the only way to know your tap is to test it.
Does Sioux City, IA water have PFAS?
Highest PFOA or PFOS result in EPA’s 2023–2025 testing was at or above 4.0 ppt, EPA’s 2024 maximum contaminant level for each. 8 PFAS compounds detected.
Has the water system in 51103 had violations?
Health-based violations since 2016: Epichlorohydrin, TTHM. All are listed as resolved.
What natural hazards affect ZIP 51103?
FEMA’s National Risk Index rates the overall natural-hazard risk here as Relatively Moderate; the highest-rated hazards are tornado (very high), riverine flooding (relatively high), winter weather (relatively high).
Are there Superfund sites near 51103?
No active Superfund site within 10 miles of the ZIP center.
Is radon a problem in Woodbury County?
Woodbury County is in EPA radon zone 1 (highest potential). Predicted average indoor radon above 4 pCi/L — EPA’s action level. Test your home.