If your St. Louis home was built before modern plumbing materials became common, the pipes, solder, and fixtures behind your walls may be older than you think. Before you open a wall, replace a faucet, or start a remodel, a water test can show whether lead is reaching your tap. This guide explains what lead is, why it can come from plumbing rather than the water supply itself, and how to test without guessing.
What Lead Is and Where It Comes From
Lead is a metal that occurs naturally in soil and rock. In household water, though, it most often comes from materials inside the home or on the service line that brings water into the house. Older solder used to join copper pipe, some brass fittings, and certain older fixtures can release lead into water that sits in them. Water that stays in a pipe overnight often carries more of this material than water that has been running for a while.
Because lead can come from plumbing as often as from the source water, a result from a neighbor's house or a general citywide report may not match what comes out of your tap. Your own pipes, your own service line, and how long the water has been sitting all shape the result.
Check Your Home Before You Test
Start with a simple walk-through. Many older St. Louis neighborhoods have a mix of materials, and a short look around the house can narrow down which taps to sample.
- Look at the kitchen and bathroom faucets and note whether the body appears to be brass or chrome plated.
- Check the visible pipe near the water heater and under sinks for copper joints and the solder used to seal them.
- Note when the house was built and whether any major plumbing work has been done since.
- Find where the cold water line enters the house, and note whether any nearby pipe looks dull or gray.
Write down what you find. You will use these notes to choose which taps to sample and how to describe them to the lab.
How to Collect a Sample
Testing is most useful when you follow the same routine every time. Use the sample container supplied by the laboratory you choose, since the lab knows how to preserve the sample for the analysis it will run.
- To see what has been sitting in the pipes, do not run any tap before collecting. Let the water stand undisturbed overnight, then collect the first sample from the cold tap you use most for drinking. This is your first-draw sample.
- Run the same tap until the water turns cold, then collect a second sample. This shows what is coming from the main line rather than the pipe closest to the fixture.
- Label each container with the room, the tap name, and the time you collected it.
- Keep the containers cool and ship them to the lab as soon as the instructions allow.
Choosing a Lab
A home test strip or a simple kit can give you a rough sense of what to expect, but it does not replace a report from a certified laboratory. Look for a lab that is certified to analyze drinking water in Missouri, and confirm that it tests for lead specifically. Ask how to ship the samples, how long results usually take, and whether the report will list the sample location and collection time for each container.
Reading the Results
A lab report lists a result for each sample, along with the reporting information the lab provides. Compare the first-draw sample with the sample taken after running the tap. A large difference suggests that fixtures or pipes near the tap are contributing. Similar results across several taps may point more toward the service line or the source water. A report is a snapshot taken on one day, so retesting after plumbing changes is a sensible habit.
What to Do Before a Remodel
If you plan to open walls or replace fixtures, test before the work begins. That gives you a baseline and lets you ask whoever is doing the work specific questions about which pipes they will disturb and how they plan to handle old solder and fittings.
- Test before demolition so you have a record of the water before the work.
- Ask the person doing the work how they will handle old solder, fittings, and any pipe they remove.
- Run new fixtures for a while after installation, then retest.
- Store each lab report with your house records so the next owner or contractor can see it.
Next Steps for St. Louis Homeowners
Begin with the walk-through, collect a first-draw sample and a flushed sample from the tap you use for drinking and cooking, and send both to a certified lab. Keep your notes with the results. If the results raise questions about your plumbing, ask a licensed plumber to inspect the lines you noted, and retest after any repairs. Start small, write everything down, and let the results guide the next decision.