Is Cayucos, CA Tap Water Safe to Drink?
Graded A+ with no contaminants above EPA limits. Here's everything we tested and how Cayucos ranks. What to do next ↓
95.7/100
waterverge.com Cayucos, CA — Water Quality Report
Cayucos's drinking water received a grade of A+ (95.7 out of 100), indicating excellent water quality. The city's 2 water systems serve approximately 4,748 residents using purchased surface water.
Lead levels were measured at 0.6 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 2 violations on record, including 2 health-based violations. All violations have been resolved.
What to know about Cayucos's water
Cayucos ranks #33 out of 694 cities in California for water quality, placing it one of the best in the state.
The city draws from surface water sources, which are more susceptible to seasonal runoff and agricultural contamination, requiring extensive multi-barrier treatment including coagulation, filtration, and disinfection.
Water quality score
See methodology →Is Cayucos, CA water safe to drink?
Based on EPA testing data, Cayucos's tap water is generally safe to drink. The water system earned a grade of A+ (95.7/100), meeting federal drinking water standards across key contaminant categories. The city's 2 water systems serve approximately 4,748 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for Cayucos
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Cayucos's water quality assessment. Grade: A+ (95.7/100).
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.
2 health-based. Contaminants: Surface Water Treatment Rule.
Key contaminant findings
Based on the most recent EPA sampling data for Cayucos's water supply.
Well within EPA limits.
Violation history
Cayucos's water system has 2 total violations on record, including 2 health-based violations. All violations have been resolved.
Flood & environmental risk
San Luis Obispo County has experienced 10 federally declared disasters since 1973. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies.
Where does Cayucos's water come from?
Cayucos's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 2 water systems serving approximately 4,748 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment.
What Cayucos 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.
Cayucos'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 Cayucos
Industrial polluters nearby
Reported releases to surface water by facilities near Cayucos, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
RANTEC POWER SYSTEMS INC LOS OSOS, CA93402 | — | — | 9.4 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
San Luis Obispo County has experienced 10 federally declared disasters since 1973. 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. | 0.6 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Cayucos compares by contaminant
Explore where Cayucos ranks among all California cities for specific contaminants.
Water source & infrastructure
Where Cayucos's water comes from
Cayucos's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
Surface water systems require multi-stage treatment including coagulation, sedimentation, filtration, and disinfection to meet EPA Safe Drinking Water Act standards.
These sources can be impacted by seasonal changes, stormwater runoff, upstream agriculture, and industrial discharge.
The system is operated by local government ownership and serves approximately 4,748 people through 2 water systems.
Water systems serving Cayucos
| System Name | PWSID | Population | Source |
|---|---|---|---|
| CAYUCOS BEACH MUTUAL WATER COMPANY | CA4010006 | 2,567 | SWP |
| MORRO ROCK MUTUAL WATER CO | CA4010015 | 2,181 | SWP |
How Cayucos compares
Full California rankings →Cayucos's score of 95.7/100 is above the average of 57/100 among major California cities. It outscores 10 of 10 nearby cities.
Nearby cities
View California rankings →About Cayucos, CA
Learn more about your water
Guides and resources related to Cayucos's water quality findings.
Explore water quality across San Luis Obispo
Frequently asked questions
Is Cayucos, CA tap water safe to drink?
Cayucos's water quality earned a grade of A+ (95.7/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #33 out of 694 cities tested in California.
What contaminants are in Cayucos's water?
Lead was measured at 0.6 ppb (90th percentile). 2 violations are on record.
How is Cayucos'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 Cayucos?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Cayucos's water come from?
Cayucos's water is sourced from Purchased surface water. The city has 2 water systems serving approximately 4,748 residents.
What health violations has Cayucos's water system had?
Cayucos has 2 health-based violations on record. The most recent violation was recorded in July 1993. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. All health violations have been resolved.
How does Cayucos's water compare to other cities?
Cayucos ranks #33 out of 694 cities in California (better than 95% of state cities) and #283 out of 15744 cities nationally (98th percentile). The grade of A+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.