Is Middletown, CA Tap Water Safe to Drink?
Graded D+, with 11 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
53.5/100
waterverge.com Middletown, CA — Water Quality Report
Middletown's drinking water received a grade of D+ (53.5 out of 100), indicating poor water quality. The city's 5 water systems serve approximately 2,557 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 97 violations on record, including 32 health-based violations. 11 remain unresolved.
What to know about Middletown's water
Middletown ranks #591 out of 694 cities in California for water quality, placing it among the lowest-rated in the state.
Middletown 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, Middletown may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 11 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Middletown, CA water safe to drink?
Middletown's drinking water has significant quality concerns based on EPA testing data. With a grade of D+ (53.5/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 5 water systems serve approximately 2,557 residents using groundwater (wells).
Recent water quality updates for Middletown
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Middletown's water quality assessment. Grade: D+ (53.5/100).
Contaminants: Lead and Copper Rule.
1 health-based. Contaminants: Public Notice, Groundwater Rule.
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.
Key contaminant findings
Based on the most recent EPA sampling data for Middletown's water supply.
Well within EPA limits.
Violation history
Middletown's water system has 97 total violations on record, including 32 health-based violations. 11 remain unresolved. 11 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 Putah C Nr Guenoc, Maacama C Nr Kellogg.
Where does Middletown's water come from?
Middletown's drinking water comes from groundwater (wells), supplied by 5 water systems serving approximately 2,557 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Putah C Nr Guenoc (river), Maacama C Nr Kellogg (river).
What Middletown residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Middletown'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.
Middletown'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
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.
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 Middletown compares by contaminant
Explore where Middletown ranks among all California cities for specific contaminants.
Water source & infrastructure
Where Middletown's water comes from
Middletown'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 2,557 people through 5 water systems.
Water bodies near Middletown
Middletown is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Middletown
| System Name | PWSID | Population | Source |
|---|---|---|---|
| CALLAYOMI COUNTY WATER DISTRICT | CA1710013 | 1,598 | GW |
| Middletown Rancheria Community Water System | 090600141 | 487 | GWP |
| ANDERSON SPRINGS CSD | CA1700502 | 373 | GW |
| LAZY S MOBILE RANCH | CA1700609 | 73 | SW |
| MOUNTAIN OF ATTENTION WATER | CA1700527 | 26 | GW |
How Middletown compares
Full California rankings →Middletown's score of 53.5/100 is on par with the average of 57/100 among major California cities. It outscores 5 of 10 nearby cities.
Nearby cities
View California rankings →ZIP codes served by Middletown
The water systems serving Middletown cover 1 ZIP code. Select any ZIP to see which water systems serve that area.
About Middletown, CA
Wikipedia →Middletown is a census-designated place (CDP) in Lake County, California, United States. Its population was 1,114 at the 2020 census, down from 1,323 at the 2010 census, which was up from 1,020 at the 2000 census. Middletown was given its name because it is halfway between Lower Lake and Calistoga, which is 17 miles (27 km) to the south. The town was severely damaged by the 2015 Valley Fire.
Learn more about your water
Guides and resources related to Middletown's water quality findings.
Explore water quality across Lake
Frequently asked questions
Is Middletown, CA tap water safe to drink?
Middletown's water quality earned a grade of D+ (53.5/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #591 out of 694 cities tested in California.
What contaminants are in Middletown's water?
Lead was measured at 0.0 ppb (90th percentile). 97 violations are on record.
How is Middletown'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 Middletown?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Middletown's water come from?
Middletown's water is sourced from Groundwater. The city has 5 water systems serving approximately 2,557 residents.
What health violations has Middletown's water system had?
Middletown has 32 health-based violations 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. 11 violations remain unresolved.
Is Middletown's groundwater at risk of contamination?
Middletown 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 97 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 Middletown's water compare to other cities?
Middletown ranks #591 out of 694 cities in California (better than 15% of state cities) and #12677 out of 15744 cities nationally (20th percentile). The grade of D+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.