Short answer: A lead service line is the pipe that brings water from the street main into a house, made of lead. EPA says lead pipes are more likely in homes built before 1986 and that, where one exists, the service line is typically the biggest source of lead in tap water. The fastest ways to find out are your water utility’s service line inventory, a careful look at the pipe where it enters the house and a lab test of the water.
Check a specific house: lead pipes or a lead service line are rated high for homes built before 1930 and medium until 1986. Open the House Age Decoder with 1925 loaded →
What a service line is
Every house on public water has a service line: the pipe that runs underground from the water main in the street to the house, usually ending at a shutoff valve and water meter inside or near the foundation. Part of it may belong to the utility and part to the property owner, depending on local rules.
In older neighborhoods, many service lines were made of lead because it was flexible and durable. EPA notes that lead pipes are more likely in older cities and in homes built before 1986, and that where a lead service line connects a home to the main, it is typically the most significant source of lead in the water. The 1986 Safe Drinking Water Act amendments banned lead pipes in new drinking-water plumbing, but lines installed earlier were not automatically replaced.
Why it matters
Lead cannot be seen, tasted or smelled in water. EPA and CDC agree there is no known safe level of lead in a child’s blood. In children, even low exposure is linked to learning and behavior problems and lower IQ; in adults, to higher blood pressure and kidney problems. EPA adds that drinking water can make up 20 percent or more of a person’s total lead exposure.
That is why knowing the service line material matters most in homes with young children or anyone pregnant, and before you buy.
Step 1: Check your utility’s service line inventory
Water systems have had to build an inventory of service line materials. Under EPA’s Lead and Copper Rule Revisions, initial inventories had to be submitted to state agencies by October 16, 2024, and each service line is classified as:
| Category | What it means |
|---|---|
| Lead | The line is lead. |
| Galvanized requiring replacement | Galvanized steel that is or was downstream of lead and must be replaced. |
| Non-lead | The line is made of another material. |
| Lead status unknown | The utility does not yet know what the line is made of. |
Many utilities publish their inventory online as a map or address lookup. If yours does not, call the utility: EPA says your water utility can tell you whether your service connection contains lead. “Lead status unknown” is common; it means nobody has confirmed the material yet, not that the line is safe or unsafe.
Step 2: Look at the pipe where it enters the house
You can often get a good clue yourself. EPA’s Protect Your Tap quick check says all you need is a penny or key and a magnet, and walks you through pictures of each pipe type. The City of St. Louis water division gives a similar method:
- Find the pipe. In the basement or utility area, find the pipe that comes through the outside wall and connects to the main shutoff valve.
- Scratch gently. Lightly scratch the pipe surface with a key or coin. St. Louis warns not to use a knife or sharp tool and not to puncture the pipe.
- Try a magnet. A strong refrigerator magnet that sticks suggests galvanized steel.
What the results usually mean, according to St. Louis’s guide:
| Material | Before scratching | After scratching | Magnet |
|---|---|---|---|
| Lead | Dull silver or gray | Shiny silver | Does not stick |
| Galvanized steel | Silver or gray | May or may not get shinier | Sticks |
| Copper | Copper-colored | Barely changes | Does not stick |
St. Louis adds that a bulging, rounded wipe joint on the pipe is a sign of lead. Plastic pipe is also used for newer service lines and is easy to recognize.
This check only tells you about the part of the pipe you can see. The buried section, or the utility’s side, may be a different material. If the result is unclear, a licensed plumber can identify the pipe.
Step 3: Test the water
Even if the service line is not lead, lead can come from other plumbing, such as older solder and brass fixtures. EPA says testing is the only sure way to know whether there are harmful amounts of lead in your water. Tests generally cost $20 to $100, and your state or local drinking water authority can provide a list of certified laboratories. Follow the lab’s instructions for collecting samples from the faucets you drink from.
EPA also notes that some states and utilities offer programs that pay for testing or replacement, so ask before you pay for either.
If the house has a lead service line
- Tell the utility what you found if it is not already in the inventory.
- Ask about replacement programs, schedules and what the owner pays.
- Test the water with a certified lab and follow the utility’s guidance while you wait.
- Plan replacement with the utility and a licensed plumber. Replacing only part of the line can have its own issues, so ask how they handle the whole line.
This guide does not give instructions for plumbing work. Pipe replacement is a job for licensed professionals and the utility.
Questions to ask
The water utility
- What does your service line inventory list for this address?
- Who owns which part of the line, and who pays for replacement?
- Do you offer free or reduced-cost testing or replacement?
The seller
- Do you know what the service line is made of? Has it been replaced? Is there paperwork?
- Has the water been tested for lead? Can I see the results?
The home inspector
- What material is the visible section of the service line where it enters the house?
- Did you see galvanized or older plumbing inside that could also affect water quality?
Your insurance company
- Does my policy cover any damage related to a failed service line?
- Is service line coverage available as an add-on?
Common misunderstandings
- “New faucets mean no lead.” The service line and older solder may still contain lead.
- “Unknown means it’s fine.” Unknown means unconfirmed. Ask the utility or check the pipe.
- “The city replaces everything automatically.” Replacement rules, timelines and costs vary by utility and state.
Quick answers
Is a lead service line illegal?
No. The 1986 rules stopped lead pipes from being installed in new drinking-water plumbing; they did not require existing lines to be removed at that time. Utilities’ inventories and replacement programs are how existing lines are being found.
Does a filter help?
Ask your utility or health department which filters they recommend, and look for one certified to reduce lead.
Before-you-buy checklist
- Look up the address in the utility’s service line inventory.
- Ask the inspector to identify the visible service line material.
- Ask the seller for any test results or replacement records.
- Arrange a certified lab water test during your inspection period.
- See what else is typical for the build year in the House Age Decoder.
Related guides
- When did they stop using lead pipes in homes?
- Galvanized pipes: years used and when to replace them
- Specialty inspections by build year
- All Plumbing & Water guides
Sources
- EPA: Basic information about lead in drinking water
- EPA: Planning and developing a service line inventory
- EPA: Protect Your Tap, a quick check for lead
- City of St. Louis Water Division: How to identify your water service line material
- EPA: Use of lead free pipes, fittings, fixtures, solder and flux
- City of St. Louis: Identify and report a lead service line