Water Quality Report · Updated October 07, 2026
ST CHARLES PWS
ST CHARLES PWS delivers tap water graded C (70/100) by TapWaterSafety.org. The utility serves approximately 73,040 residents in ST. CHARLES, Missouri using surface water (purchased). The most significant water quality concerns are: Haloacetic acids (HAA9) significantly above health guideline; Arsenic* significantly above health guideline; Haloacetic acids (HAA5) significantly above health guideline. For questions, the utility can be reached at 636-949-3239.
Is ST. CHARLES tap water safe to drink?
ST CHARLES PWS delivers tap water that earns a grade of C (70/100) from TapWaterSafety.org — an average rating, with several contaminants above health guidelines but generally compliant with US legal limits.
The utility serves 73,040 residents in ST. CHARLES, drawing from surface water (purchased). Despite being legal under US EPA standards, this water would fail the European Union's Drinking Water Directive, primarily due to haloacetic acids (haa9) significantly above health guideline.
Public testing data identifies 13 contaminants in this water above EWG's health-based guidelines, including: Haloacetic acids (HAA9), Arsenic*, Haloacetic acids (HAA5), Bromochloroacetic acid*, Total trihalomethanes (TTHMs), Chromium (hexavalent), Dichloroacetic acid, Chloroform, Bromodichloromethane, Trichloroacetic acid, Nitrate*, Atrazine*, Dibromoacetic acid. For most residents, a properly certified home filter at the kitchen tap is the most cost-effective way to reduce exposure to whatever's in your water. See our filter recommendations below, matched specifically to this utility's contaminant profile.
EPA compliance record
Official U.S. EPA records for ST CHARLES PWS (system ID MO6010707) for the last 3 years. Checked 2026-10-07.
| Rule | Type | Since | Status |
|---|---|---|---|
| Lead and Copper Rule | Missed testing or reporting | 10/01/2024 | Open |
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Quick actions for ST. CHARLES residents
Top concerns in this water
Based on the most recent EPA and EWG data, these are the most significant water quality issues for ST CHARLES PWS.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 17.8 ppb, 296x above the EWG health guideline of 0.06 ppb.
Arsenic* significantly above health guideline
Moderate concernArsenic* detected at 0.736 ppb, 184x above the EWG health guideline of 0.004 ppb.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 11.0 ppb, 110x above the EWG health guideline of 0.1 ppb.
Contact ST CHARLES PWS
Reach the utility directly for service issues, water quality concerns, or to request your Consumer Confidence Report.
General Contact
Treatment Plant
Recommended water filters for ST. CHARLES
Filters matched to the specific contaminants in this 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.
Score breakdown
This utility's overall score of 70/100 breaks down across five weighted components. Read the full methodology →
Contaminants detected — international standards comparison
Every contaminant detected, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal (the strictest US benchmark). 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 |
17.8 ppb | 0.06 | — | — | — | — | — | 296× over |
| Arsenic* Heavy metal |
0.736 ppb | 0.004 | 10.0 | 10 | 10 | 0.004 | — | 184× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
11.0 ppb | 0.1 | 60.0 | 60 | — | — | — | 110× over |
| Bromochloroacetic acid* Disinfection byproduct |
2.03 ppb | 0.02 | — | — | — | — | — | 102× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
9.11 ppb | 0.15 | 80.0 | 100 | — | — | — | 61× over |
| Chromium (hexavalent) Heavy metal |
1.2 ppb | 0.02 | — | — | — | — | — | 60× over |
| Dichloroacetic acid Disinfection byproduct |
10.2 ppb | 0.2 | — | — | — | — | — | 51× over |
| Chloroform Disinfection byproduct |
7.65 ppb | 0.4 | — | — | — | — | — | 19× over |
| Bromodichloromethane Disinfection byproduct |
0.874 ppb | 0.06 | — | — | — | — | — | 15× over |
| Trichloroacetic acid Disinfection byproduct |
0.793 ppb | 0.1 | — | — | — | — | — | 7.9× over |
| Nitrate* Inorganic |
1.02 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 7.3× over |
| Atrazine* Pesticide/Herbicide |
0.2 ppb | 0.1 | 3.0 | 0.1 | 100 | 0.15 | — | Fails EU |
| Dibromoacetic acid Disinfection byproduct |
0.036 ppb | 0.03 | — | — | — | — | — | 1.2× over |
| Chlorate Disinfection byproduct |
190.0 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Dibromochloromethane Disinfection byproduct |
0.0551 ppb | 0.1 | — | — | — | — | — | Below guideline |
| Antimony* Heavy metal |
0.315 ppb | 1.0 | 6.0 | 10 | 20 | 1 | — | Below guideline |
| Barium Heavy metal |
99.3 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Nitrate and nitrite Inorganic |
0.0147 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | Below guideline |
| 1,4-Dioxane* Semi-volatile organic compound |
0.0288 ppb | 0.35 | — | — | 50 | 1 | — | Below guideline |
| Vanadium Other |
1.34 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Selenium* Heavy metal |
1.64 ppb | 30.0 | 50.0 | 20 | 40 | 30 | — | Below guideline |
| Monochloroacetic acid* Disinfection byproduct |
2.41 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
1.05 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
1.83 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Monobromoacetic acid* Disinfection byproduct |
0.157 ppb | 25.0 | — | — | — | — | — | Below guideline |
| Aluminum* Heavy metal |
2.15 ppb | 600.0 | — | 200 | — | 600 | — | Below guideline |
| Strontium Radiological |
0.165 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Chromium (total)* Heavy metal |
1.38 ppb | — | 100.0 | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.466 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Lithium Other |
20.9 ppb | — | — | — | — | — | — | Below guideline |
| Nitrite* Inorganic |
0.0263 ppm | — | 1.0 | — | — | — | — | 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 (4th ed.), California OEHHA PHGs, EWG Tap Water Database.
ST CHARLES PWS service area
This water system serves 1 community in St. Charles County, Missouri. Click any city for its dedicated tap water quality page.
Find the right filter for ST. CHARLES water
Browse filter categories by water-quality concern. Each option below is NSF-certified for the matched contaminant type.