If your home in Arnold gets its water from a private well, lead belongs on your testing list, especially if your property sits in the south or west part of town. The EPA is addressing lead and other heavy metals in private wells tied to the Southwest Jefferson County Mining Superfund area, and well owners in that part of the county are the ones the agency is asking to sample. This guide explains what lead is, how it can reach a well, and how to collect and read a sample without guesswork.
What lead is and how it reaches a well
Lead is a metal that occurs naturally in some rock and soil, and it can also come from past mining and industrial activity. In a private well, it can reach the water in two main ways. It can move through the ground into the water-bearing layer the well draws from, or it can dissolve from plumbing parts, solder, and fittings after the water leaves the well and moves through the house. A test is the only practical way to tell which situation applies to your property.
Why south and west Arnold wells get extra attention
The Superfund designation covers an area in southwest Jefferson County, and the EPA has been working on lead and heavy metals in private wells connected to that area. If your well is in the south or west part of Arnold, or you are not sure where your property falls relative to the mapped area, check the current EPA and Missouri Department of Natural Resources information for your address. Maps and status updates change, so rely on the most recent version rather than older notes from a neighbor.
Before you collect a sample
- Confirm that your home is on a private well and not a municipal supply, since this guidance applies to private wells.
- Choose a laboratory certified for drinking water analysis in Missouri, and confirm it tests for total lead.
- Ask the lab about turnaround time, its reporting limit for lead, and whether it supplies sample containers and written instructions.
- Gather any records you have on the well, such as depth, casing, and the date it was drilled. Reviewers use these details when they interpret results.
How to collect the sample
The lab's written instructions are the final word, because sampling rules differ by test and by lab. The general approach looks like this.
- Ask the lab whether it wants a first-draw sample, a flushed sample, or a sample taken at the wellhead, and follow that choice exactly.
- Use only the bottle the lab provides. Do not rinse it or add anything to it.
- Fill the bottle to the marked line, cap it, and label it with the date, time, and sampling location.
- Keep the sample cool as the lab directs, and deliver it within the time window the lab specifies.
Reading the results
A lab report lists whether lead was detected and the reporting limit for the test. If lead was not detected, the report says so. If lead was detected, do not assume a source yet. Compare the result against the drinking water standards the EPA publishes and the guidance your state agency provides. Ask the lab or your local health department how to interpret the result and whether a repeat test makes sense. One result shows what was in the water on the day you sampled, so a single report is a starting point, not a final answer.
If lead shows up in your sample
- Repeat the test using the same procedure to confirm the result.
- Work out whether the source is the well or the plumbing inside the house by comparing a well sample with a sample from a tap inside the home.
- Talk with state and local agencies about your options and any assistance programs that may apply to your property.
- Ask your health department whether to limit the use of untreated well water for drinking and cooking until the result is clear.
Keep lead testing part of routine well care
Lead testing is one part of keeping a private well in good shape. Many Arnold well owners also check for coliform bacteria and E. coli, nitrates, iron and manganese, sulfate, and hydrogen sulfide, which causes the rotten egg smell some homeowners notice. Shallow or older wells, and wells near septic systems or farm fields, deserve closer attention. Naturally occurring radium and radon are also worth asking about in this part of the region. Many labs offer bundled panels, so ask whether lead can be added to a visit you already plan. Keep every report in one folder, and retest on a schedule your lab or health department recommends, especially after a plumbing repair, a well service, or a change in the water's taste, color, or smell.