Onaka, SD: High Radon Risk — 40/100 (2026)
1 ZIP code · 2 water systems · Updated 2026-06-03
Unlike better-scoring cities in SD, Onaka records health-based violations across a meaningful portion of its service areas — the overall safety grade is well below average.
How Onaka Compares
Data: EPA SDWIS Last verified: 2026-06-03
What You Should Know About Onaka Water
- Homes built before 1986: 92% — older plumbing may contain lead solder.
- Estimated remediation: $1,200 per household.
- CDC health risk index: 15.06 — above typical levels.
Who Supplies Your Water in Onaka
2 independent water providers serve Onaka, SD — 2 systems appear in federal records.
Overview
We track water quality and home safety data for 1 ZIP code in Onaka, South Dakota (population ~167), covering 2 community water systems serving approximately 20,786 people region-wide.
No EPA violations recorded across any ZIP codes in Onaka — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Onaka: D (40/100)
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
Onaka water systems draw from: Surface water.
Lead & Copper
- Lead data: not yet available for Onaka
- 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 |
|---|---|---|---|
| 57466 | D | Web Water Development Association | 20,750 |
All ZIP Codes in Onaka
- 57466 [D]
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 Onaka
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 Onaka
With 92% 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
Lead solder was standard in copper plumbing until federally banned in 1986; lead pipes were common in service lines pre-1970. Onaka's median build year of 1964 reflects a housing stock where these older materials are a pervasive feature — not a rare legacy — of the residential plumbing landscape.
Over half of homes in Onaka 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 Onaka Homeowners
In Onaka, the remediation-to-property-value ratio is elevated enough that homeowners who identify documented issues early have an advantage — understanding the scope, sequencing by urgency, and phasing the work against household budget capacity are the practical levers that determine whether remediation feels manageable or overwhelming at this equity tier.
At 3.0% of home value, remediation costs in Onaka represent a significant financial burden. For homes valued near the median, fixing water and safety issues could cost $800–$1,500. Home values here are 77% below the South Dakota average.
Lead Exposure Risk for Children in Onaka
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.
After the federal action removing lead-bearing solder from new plumbing took effect, building practice shifted — but 92% of the Onaka inventory predates that line. With aggregate samples near or beyond 0.015 mg/L, an in-home check moves out of the optional column into the standard list.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
What You Can Do in Onaka
- Test your water at home. City-level data shows averages — your tap may differ. NSF-certified test kits cost $20-40 and give results in days.
- Install a certified water filter. An NSF-certified pitcher or under-sink filter removes most common contaminants.
- Check your home's plumbing. With 92% of homes built before 1986, lead solder is a real possibility.
- Review your water system's CCR. Your utility publishes an annual Consumer Confidence Report with detailed test results. Request it or find it online.
Deep Dive Reports
Detailed analysis for Onaka, SD