Is Occidental, CA Tap Water Safe to Drink?
Graded A, with 2 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
90.5/100
waterverge.com Occidental, CA — Water Quality Report
Occidental's drinking water received a grade of A (90.5 out of 100), indicating excellent water quality. The city's 2 water systems serve approximately 951 residents using groundwater.
Lead levels were measured at 3.8 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 51 violations on record, including 3 health-based violations. 2 remain unresolved.
What to know about Occidental's water
Occidental ranks #127 out of 694 cities in California for water quality, placing it above average in the state.
Occidental 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, Occidental may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Occidental, CA water safe to drink?
Occidental's tap water meets most EPA standards but has areas that warrant attention. With a grade of A (90.5/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 2 water systems serve approximately 951 residents using groundwater (wells).
Recent water quality updates for Occidental
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Occidental's water quality assessment. Grade: A (90.5/100).
Contaminants: Revised Total Coliform Rule.
Federal disaster declaration (FEMA DR-3592). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-4683). 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 Occidental's water supply.
Well within EPA limits.
Violation history
Occidental's water system has 51 total violations on record, including 3 health-based violations. 2 remain unresolved. 2 violations were issued in the last 5 years.
Flood & environmental risk
Sonoma County has experienced 10 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 Russian R Nr Windsor, Laguna De Santa Rosa C Nr Sebastopol, Santa Rosa C A Willowside Rd Nr Santa Rosa, Mark West C Nr Mirabel Heights, Russian R A Hacienda Bridge Nr Guerneville.
Where does Occidental's water come from?
Occidental's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 951 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Russian R Nr Windsor (river), Laguna De Santa Rosa C Nr Sebastopol (river), Santa Rosa C A Willowside Rd Nr Santa Rosa (river), Mark West C Nr Mirabel Heights (river), Russian R A Hacienda Bridge Nr Guerneville (river).
What Occidental residents can do
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.
Occidental'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
Top industrial polluters within 10 miles of Occidental
Industrial polluters nearby
Reported releases to surface water by facilities near Occidental, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
GENERAL HYDROPONICS SANTA ROSA, CA95407 | — | — | 9.9 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Sonoma County has experienced 10 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. | 3.8 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Occidental compares by contaminant
Explore where Occidental ranks among all California cities for specific contaminants.
Water source & infrastructure
Where Occidental's water comes from
Occidental'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 951 people through 2 water systems.
Water bodies near Occidental
Occidental is located near 5 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Occidental
| System Name | PWSID | Population | Source |
|---|---|---|---|
| OCCIDENTAL COMMUNITY SERVICES DISTRICT | CA4900536 | 533 | GW |
| ALLIANCE REDWOODS CONFERENCE GROUNDS | CA4900943 | 418 | GU |
How Occidental compares
Full California rankings →Occidental's score of 90.5/100 is above the average of 57/100 among major California cities. It outscores 9 of 10 nearby cities.
Nearby cities
View California rankings →About Occidental, CA
Learn more about your water
Guides and resources related to Occidental's water quality findings.
Explore water quality across Sonoma
Frequently asked questions
Is Occidental, CA tap water safe to drink?
Occidental's water quality earned a grade of A (90.5/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #127 out of 694 cities tested in California.
What contaminants are in Occidental's water?
Lead was measured at 3.8 ppb (90th percentile). 51 violations are on record.
How is Occidental'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 Occidental?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Occidental's water come from?
Occidental's water is sourced from Groundwater. The city has 2 water systems serving approximately 951 residents.
What health violations has Occidental's water system had?
Occidental has 3 health-based violations on record. The most recent violation was recorded in May 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 2 violations remain unresolved.
Is Occidental's groundwater at risk of contamination?
Occidental 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 51 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 Occidental's water compare to other cities?
Occidental ranks #127 out of 694 cities in California (better than 82% of state cities) and #2210 out of 15744 cities nationally (86th percentile). The grade of A reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.