Thornwood, NY: High Radon Risk — 40/100 (2026)
1 ZIP code · 3 water systems · Updated 2026-06-03
Public water compliance in Thornwood falls below the NY baseline — elevated violation rates are on record.
How Thornwood Compares
Data: EPA SDWIS Last verified: 2026-06-03
What You Should Know About Thornwood Water
- Homes built before 1986: 85% — older plumbing may contain lead solder.
- Estimated remediation: $2,400 per household.
- CDC health risk index: 10.47.
Who Supplies Your Water in Thornwood
Throughout Thornwood, NY, water comes from one of 3 primary utilities out of 3 total systems — independent providers with different rate structures, infrastructure, and compliance records that vary across the service territory.
Overview
We track water quality and home safety data for 1 ZIP code in Thornwood, New York (population ~5,512), covering 3 community water systems serving approximately 29,235 people region-wide.
No EPA violations recorded across any ZIP codes in Thornwood — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Thornwood: 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
Thornwood water systems draw from: Surface water.
Lead & Copper
- Lead data: not yet available for Thornwood
- 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 |
|---|---|---|---|
| 10594 | D | PLEASANTVILLE WATER DISTRICT | 9,550 |
All ZIP Codes in Thornwood
- 10594 [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 Thornwood
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 Thornwood
With 85% 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
The median home in Thornwood was built in 1968 — a figure that places most of the city's residential stock in the era when lead solder was still standard in copper plumbing. Homes built before 1986 may have lead-soldered joints; those built before 1970 face the additional possibility of lead pipes in the service line itself.
Over half of homes in Thornwood 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 Thornwood Homeowners
Equity impact data for Thornwood lands in the favorable tier — remediation claims a small slice of what properties here are worth.
Remediation costs in Thornwood 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 89% above the New York average.
Lead Exposure Risk for Children in Thornwood
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.
Despite citywide averages serving as the standard public reference point, those aggregates cannot resolve what is happening at one specific faucet — and where 85% of Thornwood homes come from before the solder rule or where utility samples sit at or above the action mark, the gap between system data and faucet reality matters more than it does in lower-exposure communities. An in-home draw closes that gap, with certified filtration through retailer networks available where confirmed faucet results warrant additional measures.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Flood & Climate Risk in Thornwood
77 FEMA flood insurance claims are on file for Thornwood, and 100% of local ZIP codes fall within federally designated flood zones — enough to put flood exposure on the planning radar, though short of the concentrated-risk threshold where treatment-system vulnerability becomes a primary consideration.
Thornwood has a moderate flood history with 77 FEMA claims averaging $15,368 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.
What You Can Do in Thornwood
- 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 85% 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 Thornwood, NY