Seneca, KS: High Radon Risk — 70/100 (2026)
1 ZIP code · 3 water systems · Updated 2026-06-03
Drinking water tracked for Seneca by KS authorities posts above-average scores — the majority of systems are free from health-based exceedances and the city's grade sits above the state median.
How Seneca Compares
Data: EPA SDWIS Last verified: 2026-06-03
Seneca Water: The Quick Version
- Average lead level: 0.0011 mg/L.
- Homes built before 1986: 67% — older plumbing may contain lead solder.
- Estimated remediation: $2,400 per household.
- CDC health risk index: 13.71 — above typical levels.
Water Systems Serving Seneca
Structurally, Seneca, KS's water supply is divided. Federal data identifies 3 water systems in the area, with 3 providers serving the bulk of residential connections. These utilities operate independently, meaning rate-setting authority and EPA compliance accountability are distributed rather than centralized.
Overview
We track water quality and home safety data for 1 ZIP code in Seneca, Kansas, covering 3 community water systems serving approximately 3,577 people.
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: 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
Seneca water systems draw from: Groundwater, Surface water.
Lead & Copper
- Average lead level (90th percentile): 0.0011 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 |
|---|---|---|---|
| 66538 | B | Nemaha Company Rwd 3 | 2,800 |
All ZIP Codes in Seneca
- 66538 [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.
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 67% 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
Because the majority of Seneca's housing predates 1986, when lead solder was banned from new plumbing, the median build year of 1975 reflects a city where lead-era plumbing materials are common rather than exceptional.
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
Given current Seneca valuations, the remediation-to-property-value ratio is low — most homeowners are looking at a proportionally modest share that fits within routine financial planning.
Remediation costs in Seneca are relatively low compared to home values. The $1,600–$3,300 estimated range is a small fraction of median property value. Home values are 67% above the Kansas 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.
When older housing represents 67% of the local inventory or aggregate readings approach the federal action level, an in-home check becomes the standard way to translate citywide averages into the specific reality of an individual Seneca address.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Climate-Related Water Risk for Seneca
Within the NFIP's national dataset, Seneca falls in moderate-exposure territory — 2 documented incidents spanning multiple decades, with 100% of local ZIP codes sitting inside FEMA flood boundaries. That combination warrants inclusion in any thorough local water quality review.
Seneca has a moderate flood history with 2 FEMA claims averaging $13,854 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 Seneca, KS