Tap Water Quality Report
Tap water quality in CHESTERFIELD, Missouri
Tap water in CHESTERFIELD, Missouri receives a grade of C (73/100) from TapWaterSafety.org. It's served by MO AMERICAN ST LOUIS ST CHARLES COUNTIES. The most significant water quality concerns are: Haloacetic acids (HAA9) significantly above health guideline; Haloacetic acids (HAA5) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline; Arsenic detected. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in CHESTERFIELD's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving CHESTERFIELD.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 22.8 ppb, 380x above the EWG health guideline of 0.06 ppb.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 20.7 ppb, 207x above the EWG health guideline of 0.1 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 30.9 ppb, 206x above the EWG health guideline of 0.15 ppb.
Arsenic detected
Moderate concernArsenic detected at 0.4 ppb.
EPA compliance record
Official U.S. EPA records for MO AMERICAN ST LOUIS ST CHARLES COUNTIES (system ID MO6010716) for the last 3 years. Checked 2026-10-07.
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Recommended filters for CHESTERFIELD
Filters matched to the specific contaminants in CHESTERFIELD's water supply.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts. Look for NSF/ANSI 53 VOC reduction.
Reverse osmosis certified for arsenic (NSF/ANSI 58)
$429-$599Reverse osmosis certified under NSF/ANSI 58 for arsenic is the most reliable home option.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
All contaminants detected in CHESTERFIELD's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Haloacetic acids (HAA9) Disinfection byproduct |
22.8 ppb | 0.06 | — | — | — | — | — | 380× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
20.7 ppb | 0.1 | 60.0 | 60 | — | — | — | 207× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
30.9 ppb | 0.15 | 80.0 | 100 | — | — | — | 206× over |
| Arsenic Heavy metal |
0.4 ppb | 0.004 | 10.0 | 10 | 10 | 0.004 | — | 100× over |
| Dichloroacetic acid Disinfection byproduct |
17.7 ppb | 0.2 | — | — | — | — | — | 89× over |
| Chloroform Disinfection byproduct |
26.2 ppb | 0.4 | — | — | — | — | — | 65× over |
| Chromium (hexavalent) Heavy metal |
1.26 ppb | 0.02 | — | — | — | — | — | 63× over |
| Bromodichloromethane Disinfection byproduct |
3.63 ppb | 0.06 | — | — | — | — | — | 61× over |
| Trichloroacetic acid Disinfection byproduct |
1.88 ppb | 0.1 | — | — | — | — | — | 19× over |
| Dibromochloromethane Disinfection byproduct |
0.992 ppb | 0.1 | — | — | — | — | — | 9.9× over |
| Dibromoacetic acid Disinfection byproduct |
0.275 ppb | 0.03 | — | — | — | — | — | 9.2× over |
| Nitrate Inorganic |
0.459 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 3.3× over |
| Nitrate and nitrite Inorganic |
0.469 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 3.3× over |
| Atrazine Pesticide/Herbicide |
0.133 ppb | 0.1 | 3.0 | 0.1 | 100 | 0.15 | — | Fails EU |
| Chlorate Disinfection byproduct |
163.4 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
2.09 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Bromoform Disinfection byproduct |
0.0399 ppb | 0.5 | — | — | — | — | — | Below guideline |
| 1,4-Dioxane Semi-volatile organic compound |
0.023 ppb | 0.35 | — | — | 50 | 1 | — | Below guideline |
| Molybdenum Other |
1.94 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.824 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Selenium Heavy metal |
0.267 ppb | 30.0 | 50.0 | 20 | 40 | 30 | — | Below guideline |
| Manganese Heavy metal |
0.179 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| 2,4-D Pesticide/Herbicide |
0.0333 ppb | 20.0 | 70.0 | — | — | — | — | Below guideline |
| Aluminum Heavy metal |
0.667 ppb | 600.0 | — | 200 | — | 600 | — | Below guideline |
| Perfluorobutanoic Acid (PFBA) PFAS |
0.842 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.11 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| 2-Methoxyethanol Other |
0.383 ppb | — | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.639 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Lithium Other |
23.1 ppb | — | — | — | — | — | — | Below guideline |
| Nitrite Inorganic |
0.00667 ppm | — | 1.0 | — | — | — | — | Below guideline |
| Testosterone Other |
0.015 ppt | — | — | — | — | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from MO AMERICAN ST LOUIS ST CHARLES COUNTIES.