Portsmouth, NH: middle-tier water safety by the latest federal monitoring.

Data: EPA SDWIS

Overview

We track home safety data for 4 ZIP codes in Portsmouth, New Hampshire (population ~23,231), covering 3 community water systems serving approximately 43,810 people region-wide. The EPA snapshots used for this build directly map water systems to 1 of 4 ZIP codes.

1 of 1 ZIP code with a reported violation count in the available EPA record (100%) have recorded EPA violations. The available record reports no health-based violations for this measured scope.

Home Safety Score

Average Home Safety Score for Portsmouth: C (66/100)

Model 4.0.0 uses four measured components across three equally weighted domains. If a required domain is unavailable, no score is published:

Factor	What It Measures
Water Quality	EPA violations and compliance history
PFAS MCL Screen	UCMR 5 testing against the covered federal MCLs
Radon Risk	EPA radon zone classification
Annual AQI	EPA AirData county-year median with at least 90 observed days

Water Sources

Portsmouth water systems draw from: Groundwater, Surface water.

Lead & Copper

• Average lead level (90th percentile): 0.0000 mg/L (EPA action level: 0.015 mg/L)
• 0 of 1 ZIP code with known status 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

Areas with Most Violations

All ZIP Codes in Portsmouth

• 03801 [C] - 1 violation
• 03802
• 03803
• 03804

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

Reporting periods vary by source. Missing data is shown as unavailable, not as zero.

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.

Median Home Value

$647,500

Est. Remediation

$2,250

Remediation as % of home value 0.4%

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.

Historical NFIP Claim Context in Portsmouth

42

Total FEMA Flood Claims

$14,007

Avg Reported Sum With Payment Data

0%

A/V Share of Claim-Record ZIPs

Historical NFIP data for Portsmouth contains 42 flood insurance claims. Among claims with payment data, the average reported building, contents, and ICC component sum is $14,007. Among ZIP codes with claim records, 0% have an A- or V-family dominant rated zone recorded in those historical claims. This is not a complete current FEMA property-map inventory.

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. The <strong>$2,250</strong> remediation estimate shown here excludes flood insurance and is not derived from NFIP claim count.

Claim count does not establish current property risk. Check the exact address in FEMA's current map and obtain a property-specific insurance quote when relevant.

Source: historical FEMA National Flood Insurance Program (NFIP) claim records. No current FEMA property-map designation is asserted.