Many homes in St. Louis draw water from a municipal supplier, but some properties in the surrounding counties still rely on a private well. If you own one, testing is your job, not your utility's. Here is a practical checklist for what to test, when to test, and what to do with the results.
Start with a baseline
If you have never tested your well, begin with a full baseline test. Ask a certified laboratory for a panel that covers bacteria, nitrate, metals, and basic chemistry such as hardness and pH. Keep the report with your home papers. A baseline gives you a reference point, so a future change in taste, color, or smell can be compared against something measured.
What each test covers
- Total coliform and E. coli bacteria: these indicate whether surface water or a damaged well casing may be letting microbes in. Testing at least once a year is a common habit.
- Nitrate: a compound that can come from fertilizer, septic systems, or animal waste. It has no taste or smell, so only a test will reveal it.
- Metals such as lead, arsenic, and iron: lead can come from older plumbing or solder, while arsenic and iron occur naturally in some bedrock.
- Hardness and pH: these explain scale on fixtures and whether the water may be hard on pipes.
When to test beyond the schedule
- After a flood, a heavy storm, or nearby construction
- When the water changes color, smell, or taste
- After septic repairs or any work on the well itself
- When the household changes, such as a new member moving in
How to collect a sample
- Use the bottle the laboratory provides, and do not rinse it.
- Remove any aerator or hose attachment from the tap, then wipe the faucet with a clean cloth.
- Run the cold water for a few minutes unless the lab gives different instructions, then fill the bottle without touching the inside.
- Label the bottle and send it to the lab promptly, since some tests have short holding windows.
Reading the results
A lab report lists each result beside a reference level. Those levels come from published standards, and a result above one is a signal to act, not a diagnosis of anything. If bacteria appear, the common first step is disinfection of the well followed by a retest. If nitrate or metals are high, ask the lab or your county health department which treatment fits your situation and whether a different water source is needed.
Keeping a simple record
Store every report in one folder, and note the date of any repair, pump change, or septic pumping. Over time this history shows whether a problem is new or has been building quietly.
Next steps for St. Louis homeowners
This month, schedule a baseline test if you have none, check your last report for overdue items, and list what has changed in the house or yard since your last sample. If the results raise questions, your county health department can explain local requirements, which can vary between St. Louis County, St. Louis City, and the surrounding counties.