Portsmouth, NH: 4 Health Violations — 81/100 (2026)
4 ZIP codes · 5 water systems · Updated 2026-06-03
Drinking water tracked for Portsmouth by NH 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 Portsmouth Compares
Data: EPA SDWIS Last verified: 2026-06-03
What You Should Know About Portsmouth Water
- Your city's water systems recorded 12 violations in the past 5 years.
- Average lead level: 0.001 mg/L.
- Estimated remediation: $2,250 per household.
- CDC health risk index: 11.66.
Who Supplies Your Water in Portsmouth
Federal records list 5 water systems tied to Portsmouth, NH. Of those, 3 are the primary providers, meaning service conditions, rate structures, and compliance histories can differ depending on where a property sits.
Overview
We track water quality and home safety data for 4 ZIP codes in Portsmouth, New Hampshire (population ~23,231), covering 5 community water systems serving approximately 44,142 people region-wide.
4 of 4 ZIP codes (100%) have recorded EPA violations. 4 health-based violations documented.
Home Safety Score
Average Home Safety Score for Portsmouth: B (81/100)
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
Portsmouth water systems draw from: Groundwater, 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 2 (Moderate Risk)
- Zone 1 (High): 0 ZIP codes
- Zone 2 (Moderate): 4 ZIP codes
- Zone 3 (Low): 0 ZIP codes
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Stage 1 DBP Rule | Treatment Technique | 10 | 4 |
| Consumer Confidence Report Rule | Reporting | 5 | 4 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 03801 | B | 3 | 1 | Portsmouth Water Works |
| 03802 | B | 3 | 1 | Portsmouth Water Works |
| 03803 | B | 3 | 1 | Portsmouth Water Works |
| 03804 | B | 3 | 1 | Portsmouth Water Works |
All ZIP Codes in Portsmouth
- 03801 [B] — 3 violations ⚠
- 03802 [B] — 3 violations ⚠
- 03803 [B] — 3 violations ⚠
- 03804 [B] — 3 violations ⚠
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 Portsmouth
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
Top Contaminants in Portsmouth Water
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
Cost Context: What Remediation Means for Portsmouth Homeowners
In Portsmouth, the equity impact of remediation is proportionally small — not the kind of financial commitment that rises to the level of a genuine planning constraint, but a minor share of what most properties here are worth.
Remediation costs in Portsmouth are relatively low compared to home values. The $1,450–$3,200 estimated range is a small fraction of median property value. Home values are 78% above the New Hampshire average.
Lead Exposure Risk for Children in Portsmouth
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.
Lead risk in Portsmouth appears low overall, but individual homes may differ. Testing is the only way to confirm your water's lead content.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Flood & Climate Risk in Portsmouth
How does Portsmouth's flood record connect to local water quality? The NFIP documents 42 claims — enough to signal recurring events — and 25% of ZIP codes carry FEMA flood zone status. That combination places flooding in the category of factors that can periodically affect water infrastructure, even if the area isn't among the highest-exposure communities in the NFIP dataset.
Portsmouth has a moderate flood history with 42 FEMA claims averaging $7,098 per payout. 25% 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>$2,250</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 Portsmouth, NH