If your home in St. Louis was built before modern plumbing rules, the pipe that carries water from the street to your house may be made of lead. This guide explains what a lead service line is, how a homeowner can find out what is in their own plumbing, and how to test the water so the next decision is based on facts rather than guesses.
What a lead service line is
A service line is the pipe that connects the water main under the street to the plumbing inside your home. Lead is a soft gray metal that was once common in these lines. Lead can also enter tap water from solder used on older copper pipe and from some brass faucets and fittings. Lead is a substance, and the goal of testing is to learn whether it is present in your water, not to assume it is.
Find out what your line is made of
Start with records before you dig into anything. Your water provider may have service line material information for your address. Ask for it in writing if possible. If records are missing or unclear, check the pipe yourself where it enters the home, usually in a basement, crawl space, or near the water meter.
A scratch test can give a rough clue. Lightly scrape a small spot on the pipe with a key or a coin where it is accessible. Lead is dull gray and marks easily, copper shows a bright reddish metal, and galvanized steel shows a dull gray zinc coating over steel that a magnet will grab. Plastic lines are usually white, black, or blue. A scratch test is a clue, not proof, so a licensed plumber or the provider's inspection should confirm the material before you make decisions based on it.
Check the plumbing inside the house
Even if the service line is not lead, older St. Louis homes may have lead solder joints on copper pipe, or brass fixtures and faucets with lead content. Look at the solder joints under sinks and in the basement. Older faucets and valves may have no markings. If the home has had recent plumbing work, ask the person who did it what materials were used, and keep any receipts or notes.
How to test your water
Use a lab certified for drinking water testing in Missouri. Your state environmental agency keeps a list of certified labs. Ask the lab for sampling bottles and instructions before you collect anything, because the sampling method matters.
Typical steps for a lead test:
- Do not run the water before collecting the first sample. Water that has sat overnight in the pipes is what the lab usually wants for a first-draw sample.
- Collect the sample from the kitchen cold tap using the bottle the lab provides, and avoid touching the inside of the bottle.
- Label the bottle, record the date and time, and send it to the lab promptly.
- If the lab offers a second sample after running the tap, ask whether that adds useful information for your situation.
Reading your results and deciding next steps
Lab reports list each substance with a result and a reporting limit. Read the reporting limit alongside the result, because a result below that limit means the lab did not detect the substance at that level. Ask the lab or a qualified professional to explain any terms you do not understand.
If lead is found, options include talking with your water provider about the service line, having a licensed plumber replace lead components inside the home, and checking whether a filter is certified to reduce lead. Certification matters, so look for the certification mark on the filter and confirm it covers lead. Filters are a short-term step, not a replacement for removing the source.
Questions to ask your water provider
- Do your records show the material of the service line at my address?
- Has the provider tested water in this part of St. Louis, and can I see the results?
- Does the provider have a program for replacing service lines, and what are the requirements to join?
- What sampling method do you recommend for my home?
Lead testing is a practical step, and the results tell you what to do next. If you have questions about your health or someone in your household, talk with a doctor.