Thornton, NH: Lead Above EPA Limits — 53/100 (2026)
1 ZIP code · 5 water systems · Updated 2026-06-03
Within Thornton, water quality data indicates below-average safety by NH standards — independent testing is a reasonable precaution for residents whose systems show active violations.
How Thornton Compares
Data: EPA SDWIS Last verified: 2026-06-03
Key Facts for Thornton Residents
- Average lead level: 0.566 mg/L — exceeds the EPA action level of 0.015 mg/L.
- Homes built before 1986: 56% — older plumbing may contain lead solder.
- Estimated remediation: $5,560 per household.
- CDC health risk index: 11.38.
Thornton's Water Providers
Water service in Thornton, NH is split across 3 utilities out of 5 tracked federally, each operating its own infrastructure and compliance record.
Overview
We track water quality and home safety data for 1 ZIP code in Thornton, New Hampshire, covering 5 community water systems serving approximately 2,763 people.
No EPA violations recorded across any ZIP codes in Thornton — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Thornton: D (53/100)
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
Thornton water systems draw from: Groundwater.
Lead & Copper
- Average lead level (90th percentile): 0.5660 mg/L (exceeds EPA action level) (EPA action level: 0.015 mg/L)
- 1 ZIP code exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 2 (Moderate 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 |
|---|---|---|---|
| 03285 | D | Owls Nest Golf Club and Condos | 272 |
All ZIP Codes in Thornton
- 03285 [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.
Thornton Community Health Snapshot
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
Thornton Infrastructure Age
With 56% 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 1985 places Thornton'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 Thornton 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.
How Remediation Costs Compare in Thornton
Homeowners in Thornton are working with a moderate equity share for documented remediation — the commitment deserves a line in the household budget, not dismissal.
Remediation costs are moderate relative to home values in Thornton. The estimated $3,440–$7,780 range is manageable for most homeowners but still worth budgeting for. Home values are 20% below the New Hampshire average.
Thornton: Lead Risk & Vulnerable Populations
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 interior plumbing dominates the local inventory at 56% — as in Thornton — and citywide samples cross the federal benchmark, an in-home test moves from optional into a near-default step, particularly where small kids or pregnant residents share an address.
<strong>1 ZIP code</strong> (100% of the city) exceeds the EPA lead action level of 0.015 mg/L.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Thornton: Flood History & Water Damage Risk
Thornton's flood exposure sits in the moderate range: 16 NFIP claims on record and 100% of ZIP codes within FEMA-designated flood zones. Residents with private wells or older infrastructure have reasonable grounds to factor flood timing into their water quality awareness.
Thornton has a moderate flood history with 16 FEMA claims averaging $28,843 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>$5,560</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 Thornton
- Test your water at home. City-level data shows averages — your tap may differ. Lead testing is especially recommended given the area's lead levels.
- Install a certified water filter. An NSF-certified pitcher or under-sink filter removes most common contaminants.
- Check your home's plumbing. With 56% 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 Thornton, NH