Clark County, South Dakota
7 ZIP codes · Avg score 58/100 · Grade C · Updated 2026-06-04
In recent monitoring cycles, Clark County's 7 ZIP codes show a split record — several have documented water safety violations.
How Clark County Compares
How Clark County Compares
Clark County scores 2 points below the South Dakota state average (60/100) and 10 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-04
ZIP Code Risk Map
Water Quality Map: Clark County, South Dakota
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 14.1 (asthma 9.8%, diabetes 13.1%)
Estimated additional annual cost per homeowner: $677, driven primarily by water_lead
Infrastructure: 0.439% avg pipe failure probability, 86% of ZIPs at high risk
81.3% 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: $677
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
1,704 housing units in Clark 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 Clark County
Remediation costs are relatively manageable for most homeowners in Clark 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 Clark 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 Clark County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Mid-dakota Rural Water | 11,833 | 10 |
| 2 | Fordham Colony | 142 | 10 |
| 3 | Shamrock Colony | 75 | 10 |
| 4 | Clark Rural Water System | 2,325 | 5 |
| 5 | Wallace | 91 | 4 |
10 total water systems serve Clark County.
All ZIP Codes in Clark County
7 ZIP codes tracked in Clark County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 57225 | Clark | 70 | B | 0 | $144K |
| 2 | 57278 | Willow Lake | 70 | B | 0 | $203K |
| 3 | 57272 | Wallace | 67 | C | 4 | $83K |
| 4 | 57236 | Garden City | 64 | C | 1 | — |
| 5 | 57217 | Bradley | 53 | D | 0 | $103K |
| 6 | 57322 | Carpenter | 44 | D | 10 | $119K |
| 7 | 57386 | Yale | 40 | D | 0 | $131K |
Recommended Buyer Guides for Clark County
Independent picks. EPA-grounded. Matched here.
- Best Lead Paint Test Kits — 81.3% of homes built before 1978
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
Deep Dive Reports
Detailed analysis for Clark County, South Dakota
Overview
Clark County in South Dakota covers 7 ZIP codes with an average Home Safety Score of C (58/100).
3 of 7 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.