Portsmouth Water Works, NH
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2024-2024). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. The latest 90th-percentile result was reported as 0 (not detected at the lab's limit). That says the sampled homes were low, not that your home has no lead service line. Check your utility's service line inventory for your address.
Who runs the water here
Portsmouth Water Works serves about 33,000 people through 7,200 service connections, which makes it a large system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws surface water, in Rockingham County, New Hampshire. EPA system ID: NH1951010. Ask the utility on your bill for your address in their service line inventory.
Lead results over time
Against the period ending 2024 (1 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Portsmouth Water Works is 7 ppb across 10 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2024 | 0 (not detected) |
| 2024 | 1 ppb |
| 2023 | 1 ppb |
| 2023 | 1 ppb |
| 2023 | 2 ppb |
| 2022 | 1 ppb |
| 2020 | 1 ppb |
| 2019 | 1 ppb |
| 2019 | 7 ppb |
| 2017 | 0 (not detected) |
Where this result ranks
Of the 124 New Hampshire systems with a lead result, the median latest reading is 16 ppb; 62 are over 15 ppb right now and 64 have gone over at some point. Portsmouth Water Works's reported as 0 (not detected) sits at the 21st percentile in New Hampshire and the 39th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Nearby utilities
185 other systems share Rockingham County; 17 of them have a higher latest lead result than Portsmouth Water Works. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Salem Water Dept | 21,080 | 2 ppb |
| Derry Water Dept | 17,528 | 0 (not detected) |
| Seabrook Water Dept | 14,000 | 3 ppb |
| Exeter Water Dept | 12,236 | 0 (not detected) |
| Pease Trade Port | 9,900 | 0 (not detected) |
| Hampstead Area Water | 7,153 | 2 ppb |
| Londonderry | 6,255 | 4 ppb |
| Newmarket Water Works | 5,030 | 2 ppb |
| Rye Water Dist | 4,300 | 0 (not detected) |
| Raymond Water Dept | 3,300 | 1 ppb |
Next steps for Portsmouth, NH
Look up your address in Portsmouth Water Works's service line inventory. If it says lead, galvanized or unknown, test your tap. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Portsmouth Water Works whether it covers that cost before hiring anyone - many utilities now do.
These figures describe homes the utility sampled, not your tap. Only your service line record or a test of your own water answers the question for your house. Why sampled homes are the worst-case ones is in the guide to reading the number. A zero today does not rule out a jump later - the rules are tightening in 2027.