Your service line is the pipe that carries water from the public main under the street to the valve or meter at your house. In many St. Louis addresses, the homeowner is responsible for the section on the property side of the connection, even though the utility controls the main. Knowing what that pipe is made of is the first step toward deciding whether testing or replacement makes sense for your home.
Start with the records
Older homes in the city and the county often have a paper trail that answers the question. Check these sources first.
- Your water utility's service line inventory or lead service line map, which many utilities publish and which you can ask about by address.
- Old plumbing or building permits from city or county records, which sometimes list the material used for service work.
- Closing documents or inspection reports from when you bought the home, which may mention the water line.
- Invoices or records from earlier plumbing work done on your property.
Check the pipe where it enters the house
If you have a basement or crawl space, look where the line comes through the wall, usually near the main shutoff or the water meter. Note the color and surface of any exposed section before you touch it.
- Galvanized steel is a dull gray metal with a rough surface and often a zinc coating. A small magnet tends to stick to it.
- Copper looks orange-brown where it is scratched and does not hold a magnet.
- Lead is dull gray and soft. A light scratch on an exposed section may show bright metal underneath. Scratching is only a visual check, so do not dig, cut, or pry at the line yourself.
- Plastic pipes such as PEX or polyethylene are usually printed with the material name along the length of the pipe.
If the pipe is painted, wrapped, or unclear, a licensed plumber can identify it without damaging the line.
When a visual check is not enough
If the pipe is buried, covered, or the records do not settle the question, ask the utility to check its side of the connection and to tell you what it has on file for your address. Ask whether any replacement or sampling program applies to your property. Ask in writing if you can, so the answer stays on paper.
Testing tap water for metals
A visual check does not tell you what is in the water. Metals in drinking water are measured in a laboratory, not by a dip strip or a color card at the sink. Choose a certified lab that tests drinking water for the metals you care about, and follow its sampling instructions exactly. Lead is a metal that can enter tap water from some older pipes, solder, and fixtures, so a homeowner often wants to know where any metal is coming from.
A common approach is to collect a first-draw sample after the water has sat in the pipes overnight, then collect a second sample after running the tap. Comparing the two can help show whether the source is the service line, the plumbing inside the house, or a fixture. The lab report lists results, and your utility's annual report can give context, but this guide does not interpret any particular result.
Notes for St. Louis homeowners
- Keep a copy of your service line record with your home papers.
- If you rent, ask your landlord whether the service line material is known.
- If a crew digs near your line, ask whether the pipe is checked or replaced during the work.
- When you call, write down the address, the date, and the name of the person you spoke with.
What to do next
- Pull the records for your address from the utility and the permit files.
- Do the magnet and visual checks at the easiest visible entry point.
- Ask the utility what it has on file for the service line.
- If the answer is still unclear, have a licensed plumber or a certified lab help you decide on the next step.