A
85

US Water Score: A

Portsmouth, NH 03801

Rockingham County · Population served: 33,000 · Data updated July 2026

Service-area evidence: EPA service-area records associate the listed system with this ZIP. Boundaries may still overlap or change.

Water Systems Serving This Area

🏔
PORTSMOUTH WATER WORKS
Surface water · Pop. 33,000
PWSID: NH1951010
🌊
PEASE TRADE PORT
Groundwater · Pop. 9,900
PWSID: NH1951020
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NEW CASTLE WATER WORKS
Surface water · Pop. 910
PWSID: NH1661010
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HEMLOCK HAVEN
Groundwater · Pop. 207
PWSID: NH1053020
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PIPER MEADOWS PRIVATE COMMUNTY
Groundwater · Pop. 125
PWSID: NH0023010

Contaminants Detected

ContaminantDetected LevelEPA MCLHealth GuidelineStatus
Lead
19.0
15 ppb 1 ppb
Copper
1450.0
1300 ppb 300 ppb

PFAS / Forever Chemicals

8 detected 2 above comparison value

UCMR5 occurrence results are screening information, not a finding of regulatory compliance or noncompliance. PFAS rules and compliance dates are evolving.

CompoundLevelEPA MCLHealth GuidelineStatus
PFBA15.1 pptNo standard500 pptNo federal MCL shown
PFBS9.0 ppt2000 ppt100 pptBelow comparison value
PFOA7.0 ppt4 ppt4 pptAbove comparison value
PFPeA7.0 pptNo standardNo federal MCL shown
PFHxA6.0 pptNo standard400 pptNo federal MCL shown
PFHxS5.0 ppt10 ppt10 pptBelow comparison value
PFOS5.0 ppt4 ppt4 pptAbove comparison value
PFHpA3.0 pptNo standardNo federal MCL shown

Violation History (Last 5 Years)

7Total (5yr)
2Health-Based
0Major

Water Quality Summary

Understanding Your Water in Portsmouth

Tap water quality in Portsmouth, New Hampshire (03801) receives an overall grade of A (Lower record-based concern) with a score of 85 out of 100, based on analysis of EPA compliance data, contaminant testing, and violation history. This is roughly in line with the New Hampshire state average of 89. The area is served by 9 water systems providing water to approximately 33,000 people, using surface water and groundwater sources. Notably, 2 PFAS compounds exceed the EPA final MCL value used for comparison — a significant concern given the persistent nature of these chemicals. Over the past 5 years, water systems here have accumulated 7 violations, including 2 health-based violations.

Your Score 85/100 A
vs State 4 pts below New Hampshire avg (89)
vs National 10 pts above national avg (75)

What a Grade A Means

A score of 85/100 means public water-system records for Portsmouth, NH show relatively few concerns in the US Water Score model. This is an internal score, not an EPA safety rating, and it does not guarantee conditions at any specific tap.

Surface water: sourced from rivers, lakes, or reservoirs
Groundwater: drawn from underground aquifers via wells

Health Information

What These Contaminants Mean for You

⚠️

Lead in Your Water

Lead is a toxic metal that can leach from aging pipes and plumbing fixtures.

Health Effects

Even low levels of lead exposure can cause developmental delays in children, kidney damage, and cardiovascular effects in adults. The EPA action level is 15 ppb, but health experts recommend no safe level of lead in drinking water.

Common Sources

Lead enters water primarily through corrosion of lead service lines, lead solder, and brass fixtures — especially in homes built before 1986.

What You Can Do

If lead is detected above 1 ppb, consider using a certified lead-removal filter (NSF/ANSI 53) for drinking and cooking water. Run cold water for 30 seconds before use if water has been sitting in pipes.

🔶

Copper in Your Water

Copper can leach into water from copper plumbing, especially in newer homes or when water is acidic.

Health Effects

Short-term exposure above 1,300 ppb can cause gastrointestinal distress. Long-term exposure may cause liver or kidney damage. People with Wilson's disease are especially vulnerable.

Common Sources

Copper pipes, fittings, and faucets are the most common source. Corrosive (low-pH) water accelerates copper leaching.

What You Can Do

If copper levels are elevated, flush pipes by running water for 15–30 seconds before use. Reverse osmosis and distillation systems effectively remove copper.

Common Questions

Frequently Asked Questions

Based on public water-system records, Portsmouth, New Hampshire receives an internal US Water Score grade of A (Lower record-based concern) with a score of 85/100. This indicates relatively few system-level concerns in our model, but it is not an EPA safety rating and does not guarantee tap conditions inside individual homes.

ZIP code 03801 is served by 9 water systems using surface water, groundwater sources, providing water to approximately 33,000 people. Multiple source types mean your water may come from a blend of surface and underground sources.

Lead levels in the public-system record for Portsmouth, New Hampshire are 19.0 ppb, above the currently applicable EPA action level of 15 ppb. EPA's Lead and Copper Rule Improvements lower that action level to 10 ppb when the new requirements take effect. This system-level result does not measure an individual tap; consider a certified lead-removal filter and independent tap testing.

Yes — 8 PFAS compounds were detected in records associated with water serving Portsmouth, New Hampshire, and 2 results exceeded the numerical EPA MCL value used for comparison. UCMR5 occurrence results alone are not a regulatory compliance determination. PFAS rules and compliance timelines are evolving; verify current information with the utility and EPA.

Water systems serving Portsmouth, New Hampshire have received 7 violations in the last 5 years, including 2 health-based violations. Violations can range from paperwork issues (monitoring & reporting) to serious health-based violations where contaminant levels exceeded safe limits. Review the violation details above for specifics.

Based on detected contaminants (lead, PFAS, copper), residents in Portsmouth, New Hampshire should consider: Reverse osmosis (RO) system — most effective for PFAS, lead, and other contaminants. Always look for filters with NSF/ANSI certification for the specific contaminants you want to remove.

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