Before you pick a softener size, a filter, or a test kit, you need to know where your water comes from. In Lake St. Louis, most homes are on the municipal system, but some properties in the surrounding area rely on a private well. The two situations lead to different checks, different records, and different next steps, so it pays to confirm which one you have.
Why the source matters
Public water reports for the Lake St. Louis area describe the tap water as very hard, and they discuss treatment topics such as chlorine disinfection, disinfection byproducts, and pH. A municipal supply is tested and reported on a regular schedule. A private well has no such report. Its quality depends on the aquifer it draws from, the depth of the well, and the condition of the well itself.
Wells near Lake St. Louis vary. Shallow wells in river-bottom ground can show heavy iron and manganese staining. Deeper bedrock wells can carry a rotten-egg hydrogen sulfide smell. Some wells pick up nitrates from farm runoff or septic systems, and some show coliform bacteria or E. coli. Naturally occurring radium can also appear in deep eastern Missouri bedrock aquifers. The former Weldon Spring cleanup site sits within the service area, which is one reason many homeowners choose to test. Current municipal radium readings are within limits, so this is a reason to test a well, not a sign that the city supply is in trouble.
Clues that point to city water
- Your utility bill lists a water service charge for your address.
- A water meter sits in the basement, a utility room, or near the curb, with a lid or box in the yard.
- There is no well cap, well house, or buried pressure tank on the property.
- Past sale paperwork or the seller's disclosure names a municipal water provider.
Clues that point to a private well
- A cap or casing sits in the yard, often near the house, a garage, or a back fence line.
- A pressure tank, pump control box, or pump electrical feed is in a basement, crawlspace, or utility room.
- You receive no water bill for this address, but you pay for pump power or well service.
- Your property file includes a well log or driller's record from the state.
Where to look for records
Start with paperwork you already have: closing documents, inspection reports, and any disclosure forms. Ask the seller or previous owner whether a well exists and whether they have a water test on file. If you do not know the water provider, an older bill or the account holder name on past statements can answer the question. For a well, a driller's record often shows the depth, the year it was drilled, and the casing details. Keep these records together with your test results.
What to do once you know
If your home is on city water, read the most recent annual water report for the supply. Look for hardness, pH, chlorine, and disinfection byproduct terms such as TTHMs and HAA5. Those results help you decide whether a softener, a filter, or a change in habits fits your situation. The report describes the supply as a whole, so it will not tell you what your own fixtures show.
If your home has a well, testing is your responsibility. A reasonable starting list includes:
- Coliform bacteria and E. coli, collected with a sample kit from a lab and handled exactly as the lab instructs.
- Nitrates, especially if a septic system is nearby or farmland sits upslope.
- Iron and manganese, which show up as staining on sinks and fixtures.
- Hydrogen sulfide, if the water has a rotten-egg smell.
- Radium, given the regional bedrock and the nearby cleanup area.
- Hardness and pH, which affect scale buildup and how well soap lathers.
Common mistakes
- Assuming a well is safe because the water looks clear. Bacteria and many dissolved minerals are not visible.
- Assuming a home is on city water because the well cap is buried or hidden behind shrubs.
- Testing for one substance and assuming everything else is fine.
Once you know your source, you can match your next step to the right records and tests. Keep your water log, label sample dates clearly, and share results with whoever helps you plan repairs or treatment.