Every year, the utility that supplies water to St. Louis area homes publishes a water quality report. Most homeowners never open it. Before you buy a treatment system, pick a salt-free unit, or call someone about a stain or scale problem, the report is a useful place to start. It will not explain everything in your plumbing, but it will show what the supply looked like over the past year and where it came from.
Find the report for your address
Look for the report on your utility's website, or call customer service and ask for a copy by mail or email. If you rent, your landlord may already have one. Keep the latest report and the one before it. Comparing two years shows whether a problem is steady or just a one-time blip.
Check where the water comes from
The early pages usually describe the source. Some St. Louis area communities draw from rivers, some rely on wells or other groundwater, and some buy water from neighboring systems. The source matters because a river supply can shift after heavy rain, while groundwater tends to change more slowly. If the report says your water was treated at a plant, note the treatment steps it lists, since they explain why the water may taste or look different at certain times of year.
Read the table of detected substances
The core of the report is a table of substances found in the water, along with the range of results and the limit set by state and federal rules. Focus on a few items first:
- Substances that were detected at all, even if they were below the limit
- Any item marked as exceeding a limit, along with the notice and corrective steps the report describes
- Items that appear in both your old and new reports, since repeat entries show a trend
A substance being listed does not by itself mean your water is unsafe to use. It means the utility tested for it and reported what it found. The limits are the reference point for judging the results.
Hardness shows up in your fixtures
Hardness refers mainly to calcium and magnesium dissolved in the water. In St. Louis homes, hardness is the usual reason for white crust on faucets, spotting on glass shower doors, and a film on the inside of kettles and coffee makers. The report will usually list a hardness result. Use it to judge how much scale you can expect, then compare that with what you see in your home. A high reading that matches heavy scale is a reasonable explanation. A high reading with no scale at all tells you something else may be going on, such as a cleaner routine or a different water source inside the building.
What the report cannot tell you
The report reflects the water at the treatment plant or at sampling points in the distribution system. It does not show what happens inside your home. It also cannot tell you about these things:
- Old pipes, fittings, or fixtures that can add material to the water before it reaches a tap
- Changes that happen in your own water heater or fixture supply lines
- Conditions at a private well, which the utility does not test
If your home has a well, the utility report does not apply to you. A private well needs its own testing.
Pair the report with a simple home check
The report is most useful when you combine it with a few checks you can do yourself:
- Look at the water in a clear glass after it sits for a few minutes, and note any color, cloudiness, or sediment.
- Run a cold tap for a minute, then check for a metallic or chlorine smell.
- Inspect the aerator on one faucet and the inlet screen on one appliance for particles or crust.
- Ask a certified lab to test any substance you want confirmed in your own tap, rather than relying on a plant sample.
Write down what you observe and the dates. A short list is enough, and it gives you something concrete to compare against the report.
Decide your next step
Once you have read the report and checked your home, you can make a clear choice. If the report shows only ordinary items and your fixtures show light scale, you may need nothing more than routine cleaning. If the report shows a trend you want to address, or your own checks point to a problem, a lab test or a conversation with a licensed plumber is a reasonable next step. Ask any professional to explain how their recommendation relates to the specific items in your report, and get the explanation in writing before you commit.