COUNTY REPORT MO

St. Charles County, Missouri

20 ZIP codes · Avg score 78/100 · Grade B · Updated

ZipCheckup grade for St. Charles County: B.

This ZIP looks solid, with a few items worth a quick check.

Based on current EPA data, St. Charles County's 20 ZIP codes maintain an above-average drinking water safety record.

How St. Charles County Compares

St. Charles County78/100
Missouri avg72/100
National avg73/100

How St. Charles County Compares

B
County Grade
78/100
Avg Safety Score
20
ZIP Codes
13
Water Systems

St. Charles County scores 6 points above the Missouri state average (72/100) and 5 points above the national average (73/100).

Data: ZipCheckup Home Safety Score model 4.0.0; EPA SDWIS, UCMR 5, EPA radon zones, EPA AirData Last verified:

B
County Grade
78
Avg Safety Score
20
ZIP Codes
Best ZIP: 63141 (83/100)
Lowest ZIP: 63376 (65/100)
$321K
Median Home Value
$1,580
Avg Remediation (49% of home value)

ZIP Code Risk Map

Water Quality Map: St. Charles County, Missouri

Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.

A B C D F

Key Risk Factors

Health risk index: 12 (asthma 10%, diabetes 10.3%)

Estimated additional annual cost per homeowner: $1,524, driven primarily by flood

45.9% of homes built before 1978 (lead paint era)

County Health Indicators vs National Average

Asthma 10% (national: 8.9%)
Diabetes 10.3% (national: 10.5%)
Obesity 35.7% (national: 32.4%)

Black markers indicate national averages. Source: CDC PLACES, Census ACS.

Infrastructure Overview

1983
Median Build Year
45.9%
Pre-1978 Housing
37/100
Infrastructure Stress Indicator
43%
ZIPs with High Infrastructure Stress
Low
Lead Pipe Risk

Modeled area-level indicator, not a failure probability. Sources: Census ACS housing age, EPA DWINS infrastructure needs, EPA SDWIS violations, and EPA lead indicators.

Compound Risk Breakdown

Estimated additional annual cost per homeowner: $1,524

Flood $1,482/yr
Water Infrastructure $132/yr
Energy Code Gap $116/yr

Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).

Housing Age Distribution

171,032 housing units in St. Charles County

Pre-1940 2%
1940–1959 5%
1960–1979 21%
1980–1999 37%
2000+ 36%

Source: U.S. Census Bureau ACS B25034 (Year Structure Built).

Water Safety Affordability

How much it costs to fix water issues relative to home values in St. Charles County

$321K
Median Home Value
$1,580
Est. Remediation Cost
0.5%
of Home Value
Remediation as % of home value low burden

Remediation costs are relatively manageable for most homeowners in St. Charles County, representing a small fraction of property value.

Remediation includes water filtration, lead abatement, radon mitigation, and flood protection where applicable. Source: Census ACS, EPA SDWIS.

Health Outcomes vs National Average

CDC PLACES data for St. Charles County residents

Asthma 10% (US avg: 8.9%)
Diabetes 10.3% (US avg: 11%)
Obesity 35.7% (US avg: 32.4%)

Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.

Water systems serving St. Charles County

8 community water systems serving St. Charles County.

Show all 8 water systems

13 total water systems serve St. Charles County.

Systems with the most violations in St. Charles County

5 water systems with recorded EPA violations.

All ZIP Codes in St. Charles County

20 ZIP codes tracked in St. Charles County.

# ZIP Code City Safety Score Grade Violations Home Value
1 63141 Saint Louis 83 B 0 $572K
2 63301 Saint Charles 83 B 1 $249K
3 63303 Saint Charles 83 B 1 $302K
4 63304 Saint Charles 83 B 2 $331K
5 63368 O Fallon 83 B 2 $328K
6 63367 Lake Saint Louis 81 B 3 $381K
7 63366 O Fallon 77 B 10 $284K
8 63385 Wentzville 75 B 12 $321K
9 63348 Foristell 70 B 21 (1 health) $365K
10 63376 Saint Peters 65 C 4 $256K
11 63177 Saint Louis
12 63302 Saint Charles
13 63332 Augusta 2 $386K
14 63338 Cottleville
15 63346 Flinthill
16 63365 New Melle
17 63370 Olney
18 63373 Portage Des Sioux $207K
19 63378 Treloar
20 63386 West Alton $156K

Recommended Buyer Guides for St. Charles County

Eight risk categories drive the selection - PFAS exceedance, lead above EPA action level, pre-1978 housing share, EPA Radon Zone 1, flood-top-risk, wildfire-top-risk, multi-contaminant load, and a baseline fallback - and each category maps to a specific buyer-guide track that surfaces when the county data hits its threshold for that hazard signal.

Overview

St. Charles County in Missouri covers 20 tracked ZIP records with an average Home Safety Score of B (78/100) across 10 scored records.

10 of 11 ZIP codes with a reported violation count in the available EPA record have recorded EPA violations. 1 health-based violation appear in the available health breakdown.

← Back to Missouri Home Safety Profile

Data Sources

Reporting periods vary by source. Missing data is shown as unavailable, not as zero.

Frequently Asked Questions

Is water safe in St. Charles County?
St. Charles County receives a grade of B, indicating generally safe tap water across its 20 ZIP codes.
How many water systems serve St. Charles County?
St. Charles County is served by 13 public water systems that supply drinking water to residents across 20 ZIP codes.
What is the biggest environmental risk in St. Charles County?
The primary environmental risk factor in St. Charles County is flood. This contributes to an estimated additional annual cost of $1,524 per homeowner.
How old are homes in St. Charles County?
The median home build year in St. Charles County is 1983. 45.9% of homes were built before 1978, which means they may contain lead-based paint and older plumbing materials.
How does St. Charles County compare to Missouri?
St. Charles County has an average Home Safety Score of 78/100 under model 4.0.0, which is above the Missouri state average of 72/100.

How to cite this page

APA ZipCheckup. (2026). St. Charles County, MO: HSS 78/100; 1 Health Violation. https://zipcheckup.com/county/missouri/st-charles/
BibTeX
@misc{zipcheckup-county-missouri-st-charles,
  author = {{ZipCheckup}},
  title  = {{St. Charles County, MO: HSS 78/100; 1 Health Violation}},
  year   = {2026},
  url    = {https://zipcheckup.com/county/missouri/st-charles/}
}

Page version: August 2026.

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