Willow Lake, SD: High Radon Risk — 70/100 (2026)
1 ZIP code · 2 water systems · Updated 2026-06-03
Water systems in Willow Lake, SD serve households with few reported safety events.
How Willow Lake Compares
Data: EPA SDWIS Last verified: 2026-06-03
What You Should Know About Willow Lake Water
- Average lead level: 0.001 mg/L.
- Homes built before 1986: 71% — older plumbing may contain lead solder.
- Estimated remediation: $2,400 per household.
- CDC health risk index: 14.15 — above typical levels.
Who Supplies Your Water in Willow Lake
Residential water in Willow Lake, SD is supplied by 2 separate utilities — not one centralized authority. Each of those providers operates under its own service territory boundary, maintains its own distribution infrastructure, and files compliance documentation with the EPA on its own timeline. Federal data counts 2 water systems in the area, with these providers collectively accounting for the dominant share of household connections.
Overview
We track water quality and home safety data for 1 ZIP code in Willow Lake, South Dakota (population ~1,082), covering 2 community water systems serving approximately 2,580 people region-wide.
No EPA violations recorded across any ZIP codes in Willow Lake — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Willow Lake: B (70/100)
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
Willow Lake water systems draw from: Groundwater.
Lead & Copper
- Average lead level (90th percentile): 0.0010 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)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 57278 | B | Clark Rural Water System | 2,325 |
All ZIP Codes in Willow Lake
- 57278 [B]
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.
Health Outcomes in Willow Lake
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
Housing & Infrastructure in Willow Lake
With 71% 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
Federal plumbing rules changed in two stages — lead pipes were phased out before 1970, and lead solder was banned in 1986 — but in Willow Lake, where the median build year is 1965, most of the housing was already in place before those rules took effect. The materials installed under older standards remain embedded in a substantial portion of the residential inventory today.
Over half of homes in Willow Lake 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.
Cost Context: What Remediation Means for Willow Lake Homeowners
While Willow Lake homeowners face a manageable path to remediation, the equity share sits in the moderate tier — a signal that proactive budgeting matters more here than in lower-ratio markets.
Remediation costs are moderate relative to home values in Willow Lake. The estimated $1,600–$3,300 range is manageable for most homeowners but still worth budgeting for. Home values are 16% above the South Dakota average.
Lead Exposure Risk for Children in Willow Lake
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.
Locally, 71% of Willow Lake homes carry interior plumbing from the era when lead solder was still permitted in new builds, and citywide monitoring approaches or crosses the EPA action benchmark. Households can find a draw-test kit and certified filtration through verified retailers.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Flood & Climate Risk in Willow Lake
Although Willow Lake's flood history doesn't reach high-severity thresholds, NFIP data documents 3 claims and FEMA maps place 100% of ZIP codes in designated flood zones — a combined profile that makes flood-related water quality considerations a reasonable planning baseline.
Willow Lake has a moderate flood history with 3 FEMA claims averaging $14,283 per payout. 100% 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>$2,400</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.
Deep Dive Reports
Detailed analysis for Willow Lake, SD