If your home in St. Louis or the surrounding countryside runs on a private well instead of city water, you are responsible for what comes out of it. No utility samples your tap for you, and the faucet is the only place you will see what the ground is delivering. This guide walks through where to start, what a useful test covers, and how to read the results without guessing.
First, confirm you are on a well
Some homes on the outer edges of the metro area look like city homes but draw from a private well. Check your water bill. If you do not receive one, or if the property has a pump house, a buried tank, or a pressure tank in a basement or utility room, you are likely on a well. Ask whether a well record exists for the property. State agencies keep well construction records, and a record shows the depth, the casing, and the drilling date, which helps you decide what to test.
Start with a certified lab test
A home test strip gives a quick read on hardness or pH, but it is not enough for a well. For a complete picture, send a sample to a state-certified laboratory. Your county health department or the state environmental agency can point you to labs that accept private well samples. Ask for a basic panel first. It usually includes bacteria, nitrate, pH, hardness, iron, manganese, total dissolved solids, and conductivity. Add metals and other compounds based on what is known about your area and what neighbors have found.
Test for bacteria first
Bacteria tests, usually for total coliform and E. coli, show whether surface water or other contamination is reaching the well. Collect the sample exactly as the lab instructs, with clean hands and a faucet prepared the way the lab describes. A positive result is a reason to act soon, not to wait. Use boiled or otherwise treated water for drinking and cooking until the issue is resolved, and have a contractor inspect the well for a cracked casing, a loose cap, or surface water pooling near the wellhead.
Nitrate and other dissolved compounds
Nitrate comes from fertilizer, septic systems, and animal waste. It moves through soil into groundwater, so a well near a crop field, a pasture, or an older septic drain field may show it. Some bedrock aquifers in the region also carry naturally occurring substances such as arsenic, lead, or uranium, which is why a broader panel matters. The lab report lists each substance next to the standard it is compared against. Read the units and the limit column side by side so you know exactly what was measured.
Iron, manganese, and hardness
Iron and manganese cause staining, a metallic taste, and dark specks on fixtures and laundry. Hardness is the mineral load that leaves scale on heating elements and soap residue on glass. These results mostly describe how the water behaves inside your house, not whether it is contaminated. That makes them useful when you decide which equipment fits, such as an iron filter, a softener, or a salt-free conditioner, which is designed for scale control and does not remove iron or bacteria.
Read the results plainly
- Find every substance that was detected and its listed result.
- Compare each result to the limit printed on the report.
- Flag anything above a limit, then call the lab or county health office to ask what it means for your household.
- Keep the full report with your well records and your home documents.
Retest on a schedule
Water quality changes over time. Heavy rain, nearby construction, and pump or pipe repairs can all shift results. Retest for bacteria more often than the chemical panel, and retest after any repair, flood, or change in taste, color, or odor.
When to call for help
- Any bacteria detection, or a sudden change in how the water looks
- A result above a listed limit for a substance you cannot identify
- Cloudy, smelly, or discolored water that appears after rain
Bring the full lab report to a licensed well contractor or your county health office. A written plan with a retest date gives you far more to work with than a single result taken from a strip.