If you rely on a private well near Washington, a lab report is only as useful as the sample behind it. A bottle collected the wrong way can show contamination that is not in the well, or miss a problem that is. Wells are unregulated, so nobody tests yours unless you do. Here is how to collect a sample that tells you something real about your water and helps you decide what to do next.
Start with the right lab
Choose a laboratory that is certified for drinking water testing in Missouri and confirm that it accepts samples from private well owners. Ask which tests it runs, what bottles it supplies, how it wants samples cooled, and how long it holds them before analysis. Some labs offer a basic bacteria and nitrate panel. Others handle metals, hardness, and radioactive elements such as radium through separate methods, so you may need more than one order.
Follow the lab's written collection instructions over any general advice, including this guide. Preservatives, bottle types, and cooling rules differ from lab to lab.
Prepare the faucet and the bottle
- Pick a cold water faucet close to the well and ahead of any treatment equipment, including softeners, filters, and tanks. A sample taken after treatment shows what that equipment is doing, not what the well is carrying.
- Remove the aerator or screen from the faucet. Sediment and mineral crust can hold bacteria and affect metals results.
- Wash your hands well before you start. Do not touch the inside of the bottle or the lid.
- Clean the faucet outlet, and if the lab asks, sanitize it the way they describe before sampling.
- If the bottle contains a preservative, do not rinse it out or let water spill from it.
Let the water run before you fill
Run the cold water until its temperature settles and stays steady. This helps the sample reflect the well and not water that has been sitting in the pipes. Then reduce the flow to a gentle stream so you do not splash or add air to the sample. Fill the bottle to the line the lab marks, cap it right away, and avoid setting the cap down on surfaces.
Timing matters in the Washington area
Wells in Franklin County, especially those in the river-bottom area, can change after heavy rain or flooding. If your area has had a storm, a flood, or a power outage that affected the pump, test before you use the water untreated for drinking. Otherwise, sample on a regular schedule, and also sample any time you notice a change in smell, color, taste, or flow. Deeper bedrock wells can produce a rotten egg smell from hydrogen sulfide, and that is a good reason to test promptly.
What to ask the lab to test
- Coliform bacteria and E. coli, the core bacteria check for any private well.
- Nitrate, which is often linked to nearby farmland and septic systems.
- Iron and manganese, along with hardness, which relate to orange staining, dark specks, and scale.
- Radium and gross alpha, which are measured by specialized methods and are worth asking about for deeper wells.
- Hydrogen sulfide, which you can often notice by smell, but which a lab can confirm.
Keep a simple record
Write down the date, the time, the faucet you used, the weather that week, and who collected the sample. Keep the lab's paperwork with the report. A simple log lets you compare results over several years and gives any service visitor a clear picture of what has changed. Store bottles the way the lab directs, usually cool and out of direct sun, and deliver them within the holding time the lab sets.
Read the report before you act
A lab report is a set of results, and reading it takes context. Compare each result with the reporting limits and notes printed on the report itself. If a result is above a limit, or a test returns a value you did not expect, ask the lab to explain it in plain terms before you change anything in the house. Testing first keeps you from treating the wrong problem, and it gives you a documented starting point for any next step.