Is Mormon Lake, MO Tap Water Safe to Drink?
Graded B- — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
71.9/100
waterverge.com Mormon Lake, MO — Water Quality Report
Mormon Lake's drinking water received a grade of B- (71.9 out of 100), indicating fair water quality. The city's 2 water systems serve approximately 509 residents using groundwater.
Lead levels were measured at 0.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 122 violations on record, including 9 health-based violations. 35 remain unresolved.
What to know about Mormon Lake's water
Mormon Lake ranks #390 out of 509 cities in Missouri for water quality, placing it among the lowest-rated in the state.
Mormon Lake 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.
As a small community water system, Mormon Lake may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 6 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Mormon Lake, MO water safe to drink?
Mormon Lake's drinking water has significant quality concerns based on EPA testing data. With a grade of B- (71.9/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 2 water systems serve approximately 509 residents using groundwater (wells).
Recent water quality updates for Mormon Lake
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Mormon Lake's water quality assessment. Grade: B- (71.9/100).
Contaminants: Chlorine.
Contaminants: Public Notice.
1 health-based. Contaminants: Revised Total Coliform Rule.
Key contaminant findings
Based on the most recent EPA sampling data for Mormon Lake's water supply.
Well within EPA limits.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
Mormon Lake's water system has 122 total violations on record, including 9 health-based violations. 35 remain unresolved. 6 violations were issued in the last 5 years.
Where does Mormon Lake's water come from?
Mormon Lake's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 509 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Mormon Lake residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Mormon Lake'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.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Drought conditions
D2 — severe droughtCoconino County is currently in D2 (severe drought) per the U.S. Drought Monitor (week of May 5, 2026). Drought can elevate disinfection-byproduct (TTHM/HAA5) levels and taste/odor issues as utilities draw from lower reservoirs.
Source: U.S. Drought Monitor, updated weekly by NDMC, USDA, and NOAA.
Recommended water filters
Based on contaminants detected in Mormon Lake'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. | 0.0 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 1.45 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Mormon Lake compares by contaminant
Explore where Mormon Lake ranks among all Missouri cities for specific contaminants.
Water source & infrastructure
Where Mormon Lake's water comes from
Mormon Lake'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 509 people through 2 water systems.
Water systems serving Mormon Lake
| System Name | PWSID | Population | Source |
|---|---|---|---|
| CS MORMON LAKE WATER COMPANY | AZ0403014 | 353 | GW |
| TALL PINES ESTATES WATER | AZ0403024 | 156 | GW |
How Mormon Lake compares
Full Missouri rankings →Mormon Lake's score of 71.9/100 is above the average of 62/100 among major Missouri cities. It outscores 5 of 10 nearby cities.
Nearby cities
View Missouri rankings →Learn more about your water
Guides and resources related to Mormon Lake's water quality findings.
Explore water quality across Coconino
Frequently asked questions
Is Mormon Lake, MO tap water safe to drink?
Mormon Lake's water quality earned a grade of B- (71.9/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #390 out of 509 cities tested in Missouri.
What contaminants are in Mormon Lake's water?
Lead was measured at 0.0 ppb (90th percentile). 122 violations are on record.
How is Mormon Lake'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 Mormon Lake?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Mormon Lake's water come from?
Mormon Lake's water is sourced from Groundwater. The city has 2 water systems serving approximately 509 residents.
What health violations has Mormon Lake's water system had?
Mormon Lake has 9 health-based violations on record. The most recent violation was recorded in October 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 35 violations remain unresolved.
Is Mormon Lake's groundwater at risk of contamination?
Mormon Lake 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 122 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 Mormon Lake's water compare to other cities?
Mormon Lake ranks #390 out of 509 cities in Missouri (better than 23% of state cities) and #10477 out of 15744 cities nationally (34th percentile). The grade of B- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.