Is Cornville, MO Tap Water Safe to Drink?
Graded B-, with 26 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
70.7/100
waterverge.com Cornville, MO — Water Quality Report
Cornville's drinking water received a grade of B- (70.7 out of 100), indicating fair water quality. The city's 1 water system serves approximately 650 residents using groundwater.
Lead levels were measured at 10.0 ppb (90th percentile), which is within EPA limits but above recommended levels. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 136 violations on record, including 1 health-based violation. 26 remain unresolved.
What to know about Cornville's water
Cornville ranks #399 out of 509 cities in Missouri for water quality, placing it among the lowest-rated in the state.
Cornville relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
While lead levels are within EPA limits, they are above the recommended 5 ppb threshold that health organizations consider ideal. A point-of-use filter adds an extra layer of protection.
As a small community water system, Cornville may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 9 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Cornville, MO water safe to drink?
Cornville's drinking water has significant quality concerns based on EPA testing data. With a grade of B- (70.7/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 650 residents using groundwater (wells).
Recent water quality updates for Cornville
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Cornville's water quality assessment. Grade: B- (70.7/100).
Contaminants: Arsenic.
Contaminants: Arsenic.
Contaminants: Consumer Confidence Rule, Chlorine.
Key contaminant findings
Based on the most recent EPA sampling data for Cornville's water supply.
Within EPA limits but above the American Academy of Pediatrics recommended level of 1 ppb. An NSF 53-certified filter provides additional protection.
Violation history
Cornville's water system has 136 total violations on record, including 1 health-based violation. 26 remain unresolved. 9 violations were issued in the last 5 years.
Where does Cornville's water come from?
Cornville's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 650 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Creve Coeur Creek At Chesterfield (river), Creve Coeur Creek Near Creve Coeur (river), Fee Fee Creek Near Bridgeton (river), River Des Peres Near University City (river), River Des Peres Tributary At Pagedale (river).
What Cornville residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Cornville's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Recommended water filters
Based on contaminants detected in Cornville's water supply, we recommend the following filter types.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 10.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Cornville compares by contaminant
Explore where Cornville ranks among all Missouri cities for specific contaminants.
Water source & infrastructure
Where Cornville's water comes from
Cornville's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by private ownership and serves approximately 650 people through 1 water system.
Water bodies near Cornville
Cornville is located near 5 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Cornville
| System Name | PWSID | Population | Source |
|---|---|---|---|
| CS OAK CREEK PUBLIC SERVICE LLC | AZ0413042 | 650 | GW |
How Cornville compares
Full Missouri rankings →Cornville's score of 70.7/100 is above the average of 62/100 among major Missouri cities. It outscores 5 of 10 nearby cities.
Nearby cities
View Missouri rankings →About Cornville, MO
Wikipedia →Des Peres is a city in west St. Louis County, Missouri, United States. The population was 9,193 at the 2020 census.
Learn more about your water
Guides and resources related to Cornville's water quality findings.
Explore water quality across Yavapai
Frequently asked questions
Is Cornville, MO tap water safe to drink?
Cornville's water quality earned a grade of B- (70.7/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #399 out of 509 cities tested in Missouri.
What contaminants are in Cornville's water?
Lead was measured at 10.0 ppb (90th percentile). 136 violations are on record.
How is Cornville's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Cornville?
While lead levels are within EPA limits, a filter adds extra protection. Based on current data, basic filtration should suffice for additional peace of mind.
Where does Cornville's water come from?
Cornville's water is sourced from Groundwater. The city has 1 water system serving approximately 650 residents.
What health violations has Cornville's water system had?
Cornville has 1 health-based violation on record. The most recent violation was recorded in July 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 26 violations remain unresolved.
Is Cornville's groundwater at risk of contamination?
Cornville uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 136 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Cornville's water compare to other cities?
Cornville ranks #399 out of 509 cities in Missouri (better than 22% of state cities) and #10701 out of 15744 cities nationally (32th percentile). The grade of B- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Cornville's small water system affect quality?
Cornville's system serves approximately 650 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 136 violations on record.