Lead Service Line Inventory in Derry, NH: What to Know

The short answer: most lines are not lead, but many are unknown

The Derry Water Department published a lead service line inventory in 2025. It covers 4,466 service lines. Of those, none were classified as lead, 2,302 were classified as non-lead, 20 were galvanized lines requiring replacement and 2,144 were still marked unknown. Unknown means the town could not confirm the material from its records.

If your line is unknown or galvanized requiring replacement, you can request a free lead test from the town. The inventory page is the place to check your address and to find the contact details. The water department's phone is 603-432-6147.

What the inventory categories mean for you

These are the categories reported in the town's 2025 inventory.

How to find out what your line is made of

Look at where the water line enters your cellar, usually near the meter or main shutoff. A magnet will stick to steel or galvanized pipe but not to copper or lead. Lead is soft and dull gray, and a coin or key scratch leaves a bright mark. If you are unsure, ask a plumber to look, and do not scrape or cut the pipe.

The pipe inside your house and the service line outside may differ. Ownership of the line often splits between the town and the homeowner, so ask the water department where the boundary lies for your property.

What to do now

A few steps give you clarity.

1. Check the inventory for your address. The town's page lists how each line is classified.
2. Inspect the line at your cellar. Identify the material where it enters the house.
3. Request the free test if eligible. Owners of galvanized-requiring-replacement or unknown lines can ask the town.
4. Plan any replacement. A plumber can quote the work and coordinate with the water department.

Replacement is a separate project

If your line turns out to be galvanized or otherwise needs replacement, the work includes digging, a connection at the main and restoration of the surface. The plumber coordinates with the town and calls 811 before digging. Our water service line repair page explains the process and the options, and the repiping page covers the piping inside the house.

What the free test measures

A lead test checks the water that has sat in your plumbing for a period of time, usually overnight, and reports how much lead it carries. The result tells you whether lead is dissolving from a service line, a fixture or solder in the house. A test of the water is the right first step when the pipe material is not certain.

Follow the town's instructions carefully when you collect a sample. The timing, the container and the faucet matter. A result above the action level triggers follow-up, and the water department explains what comes next. A plumber does not replace the test, but a plumber can help you act on the result.

Reducing exposure while you wait for answers

Until you know your line, run the cold tap for a short time before drinking if water has sat for hours, since standing water picks up more from pipes. Use cold water for drinking and cooking, because hot water draws more metal from plumbing. Clean faucet aerators from time to time, since debris can collect there.

If you have young children or a pregnant household member, ask your doctor or the state health department what extra steps make sense. Filters certified to remove lead exist, but they must be matched to the product's certification and maintained. The state health department can explain what to look for.

What a plumber can and cannot tell you

A plumber can identify visible pipe material where the service line enters the house, point out galvanized and copper lines and advise on replacement. A plumber cannot certify the lead content of your water. That takes a laboratory test, and the town offers one for eligible owners.

A plumber can also help you understand fixtures. Older brass faucets, valves and solder can contain lead, and replacing them is a small job compared with a service line. Ask for lead-free fixtures labeled as such when you replace parts.

Keeping your own records

Write down what you learn about your service line, including the material, the date you checked it and any test results from the town. Keep the records with your house documents. If you sell, they answer buyer questions, and if you replace the line, they show what was removed.

Take a photo of the line where it enters the house, with the shutoff and the meter in view.

Nearby towns

Residents of Londonderry and Windham should check with their own water utilities, since this inventory covers Derry's system only. Homes on private wells have no town service line but should test their water, as the state recommends.

Frequently asked questions