Heavy rain and rising water can change what comes out of a tap, especially for homes in Lake St. Louis that rely on a private well. This guide covers what to check first after a storm or flood, what to test for, and when to get help. It is written for homeowners deciding their next step.
Start With What You Can See
- Check the well cap, vent, and casing for cracks, loose fittings, or signs that surface water got in.
- Look at the ground around the well for standing water, debris, or soil that has washed away.
- Pour a glass and note whether the water looks cloudy, colored, or has sediment settling at the bottom.
- Notice any new odor, especially from water that has sat in the pipes overnight.
Confirm Your Water Source
Homes on city water receive treated supply from the utility, so a storm usually affects the water through the main system rather than through the home's own equipment. Private well owners carry more of the responsibility for testing and repairs. If you are not sure which type you have, confirm it before you collect any samples, because the steps are different.
What to Test For
A basic lab panel for a private well commonly includes bacteria such as coliform and E. coli, along with nitrates. Ask the lab about additional tests that fit local conditions. In the Lake St. Louis area, iron and manganese staining is common in some river-bottom wells, and hydrogen sulfide produces a rotten-egg smell in some deeper bedrock wells. Naturally occurring radionuclides in the deep eastern Missouri bedrock aquifers are another reason some owners ask for testing. The former Weldon Spring cleanup site sits within the wider service area, so it is a practical reason to ask about radium when you request your panel. Current municipal radium readings are within limits, but municipal results do not describe a private well.
Timing Your Samples
- Wait until the water has cleared and the well has been looked over, then collect samples using the lab's written instructions.
- Use a certified lab for any bacteria result you plan to act on, rather than relying on a home kit alone.
- Retest later if another storm passes through or if the first results were unclear.
If Results Come Back Positive
A positive bacteria result means the water should not be used for drinking until your local health department or the testing lab gives you direction. Follow their guidance on disinfection and retesting. Do not treat one sample as proof that the well is safe again.
City Water Homes
If your home is on city water, check whether the utility has posted a notice for your area. Discolored water after main work or a storm is usually temporary. Run the cold tap briefly and watch whether the color clears. Write down what you saw and when, in case you need to report it.
Softener Considerations
A softener is not designed to treat bacteria, so it does not replace testing or a disinfection plan. If you have a softener, have it checked before restarting it after a flood, and keep records of the service visit. Follow any guidance from your utility or health office about whether to keep water running through the system during a notice.
Keep a Simple Record
Write down the storm date, the condition of the well, your lab results, and any changes in taste, color, or smell. A short log makes it easier to spot patterns over time and to explain your situation clearly to a lab or health office.