Nitrate in Portsmouth, NH Drinking Water
Nitrate data for Portsmouth, New Hampshire · 23,231 residents · 4 ZIP codes
Nitrate exposure in drinking water is tracked by EPA across the country; households in Portsmouth, New Hampshire are among those with confirmed detections in the public water record.
Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-06-04
Nitrate in Portsmouth Tap Water
Portsmouth, New Hampshire has 4 EPA violations related to nitrate in drinking water.
This analysis covers 23,231 residents across 4 ZIP codes in Portsmouth.
Portsmouth's overall water quality grade is B (81/100).
Is Nitrate in Portsmouth Water Safe?
If you live in an affected ZIP code, consider installing a reverse osmosis or ion exchange filter certified under NSF 53 / NSF 58 and testing your water independently.
EPA Violations for Nitrate in Portsmouth
| Date | Violation Type | Status | ZIP Code |
|---|---|---|---|
| 2025-10-01 | Nitrate (Known) | Known | 03801 |
| 2025-10-01 | Nitrate (Known) | Known | 03802 |
| 2025-10-01 | Nitrate (Known) | Known | 03803 |
| 2025-10-01 | Nitrate (Known) | Known | 03804 |
Health Effects of Nitrate
- Methemoglobinemia ("blue baby syndrome") in infants under 6 months
- Increased risk of colorectal and bladder cancer (long-term)
- Thyroid disease from chronic exposure
- Possible reproductive effects
Health risk severity: High. Governed by the National Primary Drinking Water Regulations.
How Nitrate Gets Into Drinking Water
- Agricultural fertilizer runoff
- Animal feedlot operations and manure
- Septic system leachate
- Urban stormwater and wastewater discharge
What to Do About Nitrate in Portsmouth Water
- Reverse osmosis is the most effective method for nitrate removal
- Ion exchange systems designed for nitrate can also work
- Standard carbon filters do NOT remove nitrate
- Boiling water increases nitrate concentration — never boil for nitrate
Look for filters certified under NSF 53 / NSF 58 for nitrate removal.