Grant County, South Dakota
8 ZIP codes · Avg score 48/100 · Grade D · Updated 2026-06-03
For households across Grant County's 8 ZIP codes, below-average water safety data and recurring health violations make local monitoring worthwhile — checking the specific system serving an address is the most actionable starting point.
How Grant County Compares
How Grant County Compares
Grant County scores 12 points below the South Dakota state average (60/100) and 20 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Grant 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 (asthma 9.7%, diabetes 12.8%)
Estimated additional annual cost per homeowner: $568, driven primarily by water_lead
Infrastructure: 0.38% avg pipe failure probability, 38% of ZIPs at high risk
69.7% of homes built before 1978 (lead paint era)
Violation History (2021–2023)
→ Stable trendEPA violation counts by year across Grant County water systems. Health-based shown in red, total in blue.
Peak year: 2021 with 1 violation. Past 5 years: 3 total (3 health-based).
Source: EPA SDWIS historical violations. Data may lag 6–12 months for the most recent year.
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: $568
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
2,836 housing units in Grant 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 Grant County
Remediation costs are relatively manageable for most homeowners in Grant 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 Grant 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 Grant County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | GRANT-ROBERTS RURAL WATER SYSTEM | 5,050 | 2 |
| 2 | Milbank | 3,544 | 2 |
| 3 | SUMMIT | 288 | 0 |
| 4 | BROOKINGS-DEUEL RURAL WATER SYSTEM | 6,200 | 0 |
| 5 | SOUTH SHORE | 189 | 0 |
All ZIP Codes in Grant County
8 ZIP codes tracked in Grant County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 57253 | Milbank | 66 | C | 1 | — |
| 2 | 57252 | Milbank | 65 | C | 1 | $185K |
| 3 | 57259 | Revillo | 53 | D | 0 | — |
| 4 | 57246 | Labolt | 40 | D | 0 | $90K |
| 5 | 57251 | Marvin | 40 | D | 0 | $116K |
| 6 | 57264 | Stockholm | 40 | D | 0 | $106K |
| 7 | 57265 | Strandburg | 40 | D | 0 | $123K |
| 8 | 57269 | Twin Brooks | 40 | D | 0 | $412K |
Recommended Buyer Guides for Grant County
Designed to find the guide that fits the county, not the other way around — the system reads EPA detections, FEMA hazard layers, and CDC lead-exposure markers, then outputs the categories that resolve those specific risks for households here, with NSF-certified products surfaced when the matching contaminant appears in the local monitoring data.
- Best Lead Paint Test Kits — 69.7% of homes built before 1978
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
Deep Dive Reports
Detailed analysis for Grant County, South Dakota
Overview
Grant County in South Dakota covers 8 ZIP codes with an average Home Safety Score of D (48/100).
2 of 8 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.
What You Can Do
Grant County has a grade of D. Here are steps to protect your household.
Test your tap water
Order a certified lab test kit ($20-$50) to check for lead, bacteria, and other contaminants specific to your ZIP code.
Consider a certified water filter
NSF-certified filters can remove most common contaminants. Match the filter to your test results for best protection. Try our filter matcher
Contact your water utility
Request the latest Consumer Confidence Report (CCR) from your water provider. It details exactly what was found in your water supply.
Check for lead in your home
69.7% of homes in this county were built before 1978. Older plumbing and solder can leach lead into drinking water, especially in the morning.