If your St. Louis home was built before modern plumbing rules took effect, some of the pipes, solder, or fixtures may contain lead. Lead is a metal. It can enter drinking water from plumbing materials rather than from the water supply itself, which is why a test at the street may read differently from a test at your kitchen tap. This guide explains where lead tends to show up in local homes, how to collect a sample, and how to think about the results.
Where Lead Can Hide in an Older Home
Lead can be part of household plumbing in a few places. Check these first:
- Service line: the pipe that runs from the street to the house. In older St. Louis neighborhoods it may be lead, copper, or a mix of materials.
- Interior supply pipes: some older pipes inside the home contain lead.
- Solder: joints on copper plumbing were sometimes made with lead-based solder before the rules changed.
- Fixtures and faucets: some older brass parts and fixtures may contain lead.
Start by looking where the service line enters the basement or crawlspace, and check visible joints and the material near your water meter. A simple scratch test can show whether a metal is soft and silvery, but it does not prove what the metal is, so treat it only as a clue. A licensed plumber can identify materials with more certainty, and your water provider can tell you what it knows about the service line on your street.
Why the Sample Matters
Lead usually enters water from plumbing when water sits in the pipes. The first water from a cold tap in the morning, after the home has been unused for several hours, is the most useful sample for finding lead from plumbing. Water that has run for a while has flushed out what was sitting in the pipe, so it tells you less about the pipe itself. A first draw sample and a flushed sample can read differently, and a good lab report should say which one was tested.
How to Collect a First Draw Sample
- Choose a cold kitchen tap that you use for drinking and cooking.
- Make sure no one has used water in the home for several hours, ideally overnight, and do not run water before collecting.
- Remove the aerator only if the lab instructions say to, and keep the small parts together so you can put them back.
- Fill the sample bottle from the cold tap at a steady flow without splashing, then cap it right away.
- Label the bottle with the tap location, the date, the time, and the words first draw.
- Use the bottle the lab provides and deliver it within the time window the lab specifies.
Choosing a Test Method
Home test strips and meters can screen for some metals, but they are usually not enough to confirm lead with confidence. A certified laboratory test gives a clearer answer. When you choose a lab, confirm that it is certified for the specific analysis, ask whether it accepts first draw samples, and ask how it reports results. Look for a report that lists the detection limit, since that line tells you the lowest level the lab could measure.
Reading the Results
A lab report lists the amount of lead found in the sample along with the detection limit. Read the detection limit first. If the reported result is below it, the lab did not detect lead at that level. If the result is at or above the reference the report uses, talk with a qualified professional about next steps before making decisions about your home. Compare the report against the reference it names, not against numbers from unrelated sources, since sampling method and lab method both affect what the report shows.
Next Steps if Lead Is Found
- Follow the flushing guidance from your lab or water provider before using water that has been sitting in the pipes.
- Consider a filter for drinking water only if its certification specifically covers lead, and check the rated coverage on the packaging.
- Retest after any plumbing work to confirm the result has changed.
- Ask a licensed plumber to identify the service line and interior materials, and to explain replacement options and their timing.
Questions to Answer Before You Commit to Work
- Did the lab test a first draw sample from a cold tap?
- Does the report show the detection limit and the reference it used?
- Which part of the service line is the homeowner responsible for, and which part belongs to the water provider?
- Have the interior fixtures and solder joints been identified, or only the service line?
Testing is a way to learn what is in your water, not a single answer to every question. Keep your sample records, your lab reports, and any plumbing invoices together so the history of your home is easy to follow. In St. Louis, where many homes have older plumbing, a clear record makes each next decision easier.