Seneca, SD: High Radon Risk — 66/100 (2026)
1 ZIP code · 2 water systems · Updated 2026-06-03
Across Seneca, EPA compliance data for SD sits at a moderate level — not alarming, but not uniformly clean across all service areas either.
How Seneca Compares
Data: EPA SDWIS Last verified: 2026-06-03
Seneca Water: The Quick Version
- Average lead level: 0.001 mg/L.
- Homes built before 1986: 53% — older plumbing may contain lead solder.
- Estimated remediation: $1,200 per household.
- CDC health risk index: 15.06 — above typical levels.
Water Systems Serving Seneca
Water service in Seneca, SD is split across 2 utilities out of 2 tracked federally, each operating its own infrastructure and compliance record.
Overview
We track water quality and home safety data for 1 ZIP code in Seneca, South Dakota (population ~275), covering 2 community water systems serving approximately 20,775 people region-wide.
No EPA violations recorded across any ZIP codes in Seneca — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Seneca: C (66/100)
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
Seneca water systems draw from: Surface water.
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 |
|---|---|---|---|
| 57473 | C | Web Water Development Association | 20,750 |
All ZIP Codes in Seneca
- 57473 [C]
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.
CDC Health Data for Seneca
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
How Old Is Seneca's Housing Stock?
With 53% 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
Two dates define the high-risk tiers of residential plumbing from a lead standpoint: 1970, before which lead pipes were commonly installed for service connections, and 1986, before which lead solder was standard in copper plumbing. A median build year of 1962 places Seneca's housing distribution well within that older risk zone. The bar chart above breaks down how much of the stock falls into each era — and the pre-1986 share alone represents more than half the residential inventory, making plumbing-era risk a defining characteristic of the local water safety picture.
Over half of homes in Seneca 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.
Seneca: Remediation Cost in Perspective
In Seneca, documented water and safety issues can be addressed without making a meaningful dent in home equity — the financial proportionality here is favorable, and the commitment fits within standard property planning frameworks.
Remediation costs in Seneca are relatively low compared to home values. The $800–$1,500 estimated range is a small fraction of median property value. Home values are 9% below the South Dakota average.
Protecting Children from Lead in Seneca
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.
Reading the local data together points toward a structural gap that matters more here than in low-exposure communities. 53% of Seneca stock comes from the pre-rule era, and citywide monitoring either approaches or sits beyond the federal benchmark under Lead and Copper Rule sampling. A baseline kit fits the routine-diligence category, with certified filtration available via retailer networks where confirmed faucet results warrant additional measures.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
What You Can Do in Seneca
- 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 53% of homes built before 1986, lead solder is a real possibility.
Deep Dive Reports
Detailed analysis for Seneca, SD