Is Crowley Lake, CA Tap Water Safe to Drink?
Graded B+, with 8 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
83.9/100
waterverge.com Crowley Lake, CA — Water Quality Report
Crowley Lake's drinking water received a grade of B+ (83.9 out of 100), indicating good water quality. The city's 4 water systems serve approximately 526 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 77 violations on record, including 5 health-based violations. 8 remain unresolved.
What to know about Crowley Lake's water
Crowley Lake ranks #293 out of 694 cities in California for water quality, placing it mid-range in the state.
Crowley 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, Crowley Lake may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Crowley Lake, CA water safe to drink?
Crowley Lake's drinking water has significant quality concerns based on EPA testing data. With a grade of B+ (83.9/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 4 water systems serve approximately 526 residents using groundwater (wells).
Recent water quality updates for Crowley Lake
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Crowley Lake's water quality assessment. Grade: B+ (83.9/100).
1 health-based. Contaminants: LEAD AND COPPER RULE REVISIONS.
Federal disaster declaration (FEMA DR-3592). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3591). Flood event — may have impacted local water infrastructure.
Contaminants: Revised Total Coliform Rule.
Contaminants: Revised Total Coliform Rule.
Key contaminant findings
Based on the most recent EPA sampling data for Crowley Lake's water supply.
Well within EPA limits.
Violation history
Crowley Lake's water system has 77 total violations on record, including 5 health-based violations. 8 remain unresolved. 3 violations were issued in the last 5 years.
Flood & environmental risk
Mono County has experienced 8 federally declared disasters since 1969. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Hot C A Flume Nr Mammoth Lakes.
Where does Crowley Lake's water come from?
Crowley Lake's drinking water comes from groundwater (wells), supplied by 4 water systems serving approximately 526 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Hot C A Flume Nr Mammoth Lakes (river).
What Crowley Lake residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Crowley 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.
Crowley Lake's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Flood & disaster history
Mono County has experienced 8 federally declared disasters since 1969. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
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 |
Lead level trend (90th percentile)
See how Crowley Lake compares by contaminant
Explore where Crowley Lake ranks among all California cities for specific contaminants.
Water source & infrastructure
Where Crowley Lake's water comes from
Crowley 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 526 people through 4 water systems.
Water bodies near Crowley Lake
Crowley Lake is located near 1 notable water body. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Crowley Lake
| System Name | PWSID | Population | Source |
|---|---|---|---|
| CROWLEY LAKE TRAILER PARK | CA2600547 | 230 | GW |
| CROWLEY LAKE MUTUAL WATER COMPANY | CA2600546 | 175 | GW |
| SUNLAND VILLAGE MOBILE HOME PARK | CA1400144 | 73 | GW |
| ABERDEEN WATER SYSTEM | CA1400020 | 48 | GW |
How Crowley Lake compares
Full California rankings →Crowley Lake's score of 83.9/100 is above the average of 57/100 among major California cities. It outscores 8 of 10 nearby cities.
Nearby cities
View California rankings →About Crowley Lake, CA
Learn more about your water
Guides and resources related to Crowley Lake's water quality findings.
Explore water quality across Mono
Frequently asked questions
Is Crowley Lake, CA tap water safe to drink?
Crowley Lake's water quality earned a grade of B+ (83.9/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #293 out of 694 cities tested in California.
What contaminants are in Crowley Lake's water?
Lead was measured at 0.0 ppb (90th percentile). 77 violations are on record.
How is Crowley 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 Crowley Lake?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Crowley Lake's water come from?
Crowley Lake's water is sourced from Groundwater. The city has 4 water systems serving approximately 526 residents.
What health violations has Crowley Lake's water system had?
Crowley Lake has 5 health-based violations on record. The most recent violation was recorded in October 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 8 violations remain unresolved.
Is Crowley Lake's groundwater at risk of contamination?
Crowley 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 77 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 Crowley Lake's water compare to other cities?
Crowley Lake ranks #293 out of 694 cities in California (better than 58% of state cities) and #6208 out of 15744 cities nationally (61th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.