Is Lower Lake, CA Tap Water Safe to Drink?
Graded B+, with 9 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
83.8/100
waterverge.com Lower Lake, CA — Water Quality Report
Lower Lake's drinking water received a grade of B+ (83.8 out of 100), indicating good water quality. The city's 4 water systems serve approximately 1,579 residents using groundwater.
Lead levels were measured at 8.0 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 61 violations on record, including 3 health-based violations. 9 remain unresolved.
What to know about Lower Lake's water
Lower Lake ranks #297 out of 694 cities in California for water quality, placing it mid-range in the state.
Lower 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.
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, Lower Lake may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Lower Lake, CA water safe to drink?
Lower Lake's drinking water has significant quality concerns based on EPA testing data. With a grade of B+ (83.8/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 4 water systems serve approximately 1,579 residents using groundwater (wells).
Recent water quality updates for Lower Lake
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Lower Lake's water quality assessment. Grade: B+ (83.8/100).
Contaminants: Lead and Copper Rule.
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: Lead and Copper Rule.
Key contaminant findings
Based on the most recent EPA sampling data for Lower Lake'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
Lower Lake's water system has 61 total violations on record, including 3 health-based violations. 9 remain unresolved. 2 violations were issued in the last 5 years.
Flood & environmental risk
Lake County has experienced 8 federally declared disasters since 1964. 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 Cache C Nr Lower Lake, Putah C Nr Guenoc, Clear Lk A Mooring Oa-09 Nr Clearlake Oaks.
Where does Lower Lake's water come from?
Lower Lake's drinking water comes from groundwater (wells), supplied by 4 water systems serving approximately 1,579 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Cache C Nr Lower Lake (river), Putah C Nr Guenoc (river), Clear Lk A Mooring Oa-09 Nr Clearlake Oaks (lake).
What Lower Lake residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Lower 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.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Lower 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
Superfund sites within 10 miles of Lower Lake
Superfund sites nearby
Federally tracked hazardous-waste sites on the EPA National Priorities List. Proximity does not necessarily indicate tap-water contamination — the connection depends on hydrology and treatment.
- SULPHUR BANK MERCURY MINE7.2 mi
Source: EPA Superfund National Priorities List
Flood & disaster history
Lake County has experienced 8 federally declared disasters since 1964. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Lower 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. | 8.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Lower Lake compares by contaminant
Explore where Lower Lake ranks among all California cities for specific contaminants.
Water source & infrastructure
Where Lower Lake's water comes from
Lower 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 local government ownership and serves approximately 1,579 people through 4 water systems.
Water bodies near Lower Lake
Lower Lake is located near 3 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Lower Lake
| System Name | PWSID | Population | Source |
|---|---|---|---|
| LOWER LAKE COUNTY WATER DISTRICT | CA1710010 | 1,326 | GW |
| CDF-KONOCTI CONSERVATION CAMP NO. 27 | CA1710800 | 100 | GW |
| SUNRISE SHORE MUTUAL WATER COMPANY | CA1700536 | 83 | GW |
| BAYCLIFF WATER | CA1700606 | 70 | GW |
How Lower Lake compares
Full California rankings →Lower Lake's score of 83.8/100 is above the average of 57/100 among major California cities. It outscores 8 of 10 nearby cities.
Nearby cities
View California rankings →About Lower Lake, CA
Learn more about your water
Guides and resources related to Lower Lake's water quality findings.
Explore water quality across Lake
Frequently asked questions
Is Lower Lake, CA tap water safe to drink?
Lower Lake's water quality earned a grade of B+ (83.8/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #297 out of 694 cities tested in California.
What contaminants are in Lower Lake's water?
Lead was measured at 8.0 ppb (90th percentile). 61 violations are on record.
How is Lower 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 Lower Lake?
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 Lower Lake's water come from?
Lower Lake's water is sourced from Groundwater. The city has 4 water systems serving approximately 1,579 residents.
What health violations has Lower Lake's water system had?
Lower Lake has 3 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. 9 violations remain unresolved.
Is Lower Lake's groundwater at risk of contamination?
Lower 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 61 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 Lower Lake's water compare to other cities?
Lower Lake ranks #297 out of 694 cities in California (better than 57% of state cities) and #6273 out of 15744 cities nationally (60th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.