Mendham, NJ: High Radon Risk — 45/100 (2026)
1 ZIP code · 3 water systems · Updated 2026-06-03
Drinking water quality in Mendham has lagged behind NJ benchmarks — documented violations keep the safety grade low.
How Mendham Compares
Data: EPA SDWIS Last verified: 2026-06-03
Key Facts for Mendham Residents
- Homes built before 1986: 71% — older plumbing may contain lead solder.
- Estimated remediation: $3,000 per household.
- CDC health risk index: 9.89.
Mendham's Water Providers
Water service in Mendham, NJ is split across 3 utilities out of 3 tracked federally, each operating its own infrastructure and compliance record.
Overview
We track water quality and home safety data for 1 ZIP code in Mendham, New Jersey (population ~9,771), covering 3 community water systems serving approximately 279,889 people region-wide.
No EPA violations recorded across any ZIP codes in Mendham — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Mendham: D (45/100)
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
Mendham water systems draw from: Groundwater.
Lead & Copper
- Lead data: not yet available for Mendham
- 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 |
|---|---|---|---|
| 07945 | D | NJ AMERICAN WATER - SHORT HILLS | 217,230 |
All ZIP Codes in Mendham
- 07945 [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.
Mendham 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
Mendham Infrastructure Age
With 71% 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
Decades of residential development in Mendham took place before the two main regulatory milestones that reduced plumbing-era lead risk: the phase-out of lead pipes before 1970, and the federal ban on lead solder in 1986. With a median build year of 1975, the housing stock here is anchored in that earlier period. The distinction between pre-1970 and 1970-to-1986 construction matters: the oldest homes may have lead pipes in the service line and lead solder in the copper joints, while the 1970-to-1986 tier still carries the solder risk even after lead pipes became less common. Together, these two risk layers affect a majority of the residential properties in the city — a fact the aggregate water quality data doesn't directly reveal.
Over half of homes in Mendham 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 Mendham
Low proportionality — that's the Mendham picture when remediation costs are placed against typical home equity.
Remediation costs in Mendham are relatively low compared to home values. The $2,000–$4,100 estimated range is a small fraction of median property value. Home values are 85% above the New Jersey average.
Mendham: 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.
Households with kids in the home — for whom CDC guidance places particular weight on minimizing exposure — face a specific local picture in Mendham. 71% of homes here come from the pre-rule era, and aggregate utility samples either approach or cross 0.015 mg/L. A baseline draw-test kit and certified lead-removal filtration are available via retailer networks for households confirming conditions at a specific tap.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Mendham: Flood History & Water Damage Risk
A moderate NFIP record for Mendham — 32 insurance claims paired with 100% of ZIP codes in FEMA flood zones — points to a flood history where water-quality pathways have likely been periodically relevant.
Mendham has a moderate flood history with 32 FEMA claims averaging $6,062 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>$3,000</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 Mendham
- 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 71% 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 Mendham, NJ