Water Quality in Lake Saint Louis, MO: No Violations - Grade C
Grade C · Score 55/100 · 2 water systems · Updated 2026-07-18
Lake Saint Louis's water has moderate compliance issues. Residents in affected areas should consider filtration.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-07-18
Within the water supply network of Lake Saint Louis, MO, no EPA violations appear anywhere in the federal compliance record - 2 public water systems are tracked here, and not one has been cited for an MCL exceedance, a monitoring failure, or any other reportable compliance event.
Water Quality by ZIP Code in Lake Saint Louis
Lake Saint Louis is covered by a single ZIP code, so one water-quality profile applies citywide. See the contaminant data below.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 63367 | C | 55 | 0 | 0 | View report → |
Water Quality Overview
Lake Saint Louis, Missouri receives a water quality grade of C with an overall score of 55 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
No EPA violations have been recorded for the 2 water systems serving Lake Saint Louis. This is a positive indicator, though it does not guarantee the absence of all contaminants - some substances (like PFAS) are not yet fully regulated.
What Grade C Means
A grade of C indicates moderate compliance issues. Lake Saint Louis's water systems have some violations that warrant attention. While the water may still be safe for most people, residents in affected ZIP codes should consider additional testing or filtration.
Lead Levels
Lead testing data for Lake Saint Louis is currently being collected. The EPA requires all community water systems to test for lead under the Lead and Copper Rule.
Radon Risk
Lake Saint Louis is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving Lake Saint Louis
Lake Saint Louis is served by 2 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 27,893 people across 1 ZIP code.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
The EPA has taken 8 enforcement actions against water systems serving Lake Saint Louis. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Lake Saint Louis
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels, violation history, and safety scores
Request your CCR - your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test - certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration - NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories - monitor your local utility website and local news for boil water advisories or system alerts
EPA Enforcement History
The EPA and state regulators have taken 8 enforcement actions against water systems serving Lake Saint Louis. Recent actions:
| Date | Action Type |
|---|---|
| 2025-09-03 | State Order Extension |
| 2025-08-22 | State Informal Action |
| 2025-07-21 | State Informal Action |
| 2025-07-21 | State Informal Enforcement |
| 2022-07-22 | State Informal Action |
| 2022-07-06 | State Order Extension |
| 2021-08-02 | State Informal Action |
| 2021-08-02 | State Informal Enforcement |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-09-03.
Lake Saint Louis vs. Nearby Missouri Cities
How Lake Saint Louis's water quality compares to similar cities in Missouri:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Lake Saint Louis | C | 0 | 2 | 27,893 |
| Festus | B | 1 | 12 | 27,913 |
| Warrensburg | B | 1 | 6 | 27,509 |
| Branson | B | 8 | 9 | 28,295 |
Common Questions About Lake Saint Louis Water
These are the most common questions residents search for about water quality in Lake Saint Louis, Missouri:
Is Lake Saint Louis water hard or soft? Water hardness varies by source. Lake Saint Louis's 2 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Lake Saint Louis tap water? Lake Saint Louis's water receives a grade of C (55/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for Lake Saint Louis? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Lake Saint Louis vs. Missouri Average
Understanding how Lake Saint Louis compares to the broader Missouri average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below - water quality can vary significantly even within Lake Saint Louis.
ZIP Codes in Lake Saint Louis
Lake Saint Louis spans 1 ZIP code. Each ZIP code has its own water quality profile based on the specific water system serving that area. Check each ZIP code for detailed contaminant data, violation history, and system information.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Updated daily.