01The verdict: is Cornville water safe?
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).
26 unresolved violations on record
EPA records show open compliance items for this system. Most are administrative, but unresolved items are worth watching.
See what was cited ↓650 people, 1 system
All figures on this page come from federal EPA compliance and testing data for the systems serving this city.
See the systems ↓9 violations in the last five years
Recent compliance history is the best predictor of future problems — the year-by-year record is below.
See the record ↓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.
Cornville ranks #385 out of 487 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.
02What's in Cornville's water
Every contaminant flagged in Cornville, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.
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 |
Cities ranked by 90th-percentile lead PF PFAS in Missouri
Cities ranked by compounds detected Cu Copper in Missouri
Cities ranked by 90th-percentile copper
03Cornville's ten-year track record
Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 136 violations on record, including 1 health-based violation. 26 remain unresolved.
3 of the last ten years were clean. The numbered years had EPA violations — red when any were health-based, amber when they were paperwork or missed-testing issues.
▼ Down 26 ppb since 2006. Latest reading: 10 ppb (2025) — 67% of the action level. Sampled at higher-risk homes (90th percentile).
04Where Cornville's water comes from
Cornville's drinking water is drawn from underground aquifers through wells.
Groundwater
Underground aquifers reached by wells — naturally filtered, but can carry minerals like arsenic and nitrate.
Local treatment
Groundwater generally needs less treatment — typically disinfection and, where needed, mineral removal.
1 system
1 water system, operated under private ownership.
650 people
Residents served across Cornville's service area.
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.
| System name | PWSID | Population | Source |
|---|---|---|---|
| CS OAK CREEK PUBLIC SERVICE LLC | AZ0413042 | 650 | Groundwater |
Water bodies near Cornville
These water bodies shape the regional watershed and can indirectly affect groundwater quality.
05How Cornville compares
Scores for nearby Missouri cities on one line, with the average marked.
dashed line = Missouri average (67/100)
Cornville scores 70.7/100 — on par with the Missouri average of 67/100. It outscores 4 of 10 nearby cities. Full Missouri rankings →
74.8 / 100BKansas City, MO
79.2 / 100FSpringfield, MO
37.1 / 100CColumbia, MO
61.4 / 100FO Fallon, MO
43.4 / 100FDes Peres, MO
36.6 / 100
Compare all cities in the county — grades, violations, and contaminant data side by side.→
06What to do at home
Steps matched to what testing actually found in Cornville's water — not generic advice.
Filter drinking & cooking water
NSF-certified water filter. Lead detected at 10.0 ppb
Compare tested filters →Flush taps & check your service line
Lead leaches from pipes as water sits. Run cold water 30 seconds before drinking (especially mornings), and ask the utility whether your address still has a lead service line.
Lead risks explained →Watch for Cornville alerts
We refresh EPA data monthly and surface new violations, advisories, and boil-water notices for your county on this page.
All water alerts →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 #385 out of 487 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 #385 out of 487 cities in Missouri (better than 21% of state cities) and #10555 out of 15382 cities nationally (31th 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.