Union County, South Dakota
4 ZIP codes · Avg score 62/100 · Grade C · Updated 2026-06-04
Current EPA records place Union County in the middle tier for drinking water safety, with 4 ZIP codes showing a range of outcomes.
How Union County Compares
How Union County Compares
Union County scores 2 points above the South Dakota state average (60/100) and 6 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-04
Key Risk Factors
Health risk index: 12 (asthma 9.6%, diabetes 10.6%)
Estimated additional annual cost per homeowner: $1,498, driven primarily by flood
Infrastructure: 0.325% avg pipe failure probability, 25% of ZIPs at high risk
55.5% of homes built before 1978 (lead paint era)
County Health Indicators vs National Average
Black markers indicate national averages. Source: CDC PLACES, Census ACS.
Infrastructure Overview
Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $1,498
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
6,044 housing units in Union County
Source: U.S. Census Bureau ACS B25034 (Year Structure Built).
Water Safety Affordability
How much it costs to fix water issues relative to home values in Union County
Remediation costs are relatively manageable for most homeowners in Union County, representing a small fraction of property value.
Remediation includes water filtration, lead abatement, radon mitigation, and flood protection where applicable. Source: Census ACS, EPA SDWIS.
Health Outcomes vs National Average
CDC PLACES data for Union County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water Systems with Most Violations
Top 5 systems in Union County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | South Lincoln Rural Water System | 5,250 | 3 |
| 2 | Clay Rural Water System | 4,780 | 3 |
| 3 | Alcester | 820 | 3 |
| 4 | Elk Point | 2,124 | 0 |
| 5 | North Sioux City | 3,042 | 0 |
7 total water systems serve Union County.
All ZIP Codes in Union County
4 ZIP codes tracked in Union County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 57001 | Alcester | 67 | C | 3 | $159K |
| 2 | 57025 | Elk Point | 65 | C | 0 | $226K |
| 3 | 57038 | Jefferson | 60 | C | 0 | $281K |
| 4 | 57049 | North Sioux City | 55 | C | 0 | $406K |
Recommended Buyer Guides for Union County
Editorial methodology pairs each documented risk in this county with the buyer category that addresses it, drawing on water-quality detections, housing-stock lead exposure, EPA Radon Zone designation, and FEMA flood and wildfire ratings. NSF-certified options surface where applicable, and products that match the specific contaminant take priority.
- Best Lead Paint Test Kits — 55.5% of homes built before 1978
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
- Best Sump Pumps — Flood is the top compound risk factor
- Best Mold Test Kits — Flood-driven moisture and mold risk
Overview
Union County in South Dakota covers 4 ZIP codes with an average Home Safety Score of C (62/100).
1 of 4 ZIP codes have recorded EPA violations. All violations are monitoring/reporting type.
← Back to South Dakota water quality report
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Updated daily.