01The verdict: is Stinson Beach water safe?
Stinson Beach's tap water meets most EPA standards but has areas that warrant attention. With a grade of A- (86.1/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 583 residents using surface water (rivers, lakes, or reservoirs).
Copper is over its legal limit
Measured at 1.60 mg/L against the EPA Action Level of 1.3 mg/L. The ledger below shows how far over — and which filter removes it.
See the measurement ↓Lead is well under the limit
90th-percentile lead is 0.0 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.
See the trend ↓1 violation in the last five years
Recent compliance history is the best predictor of future problems — the year-by-year record is below.
See the record ↓Stinson Beach's drinking water received a grade of A- (86.1 out of 100), indicating good water quality. The city's 1 water system serves approximately 583 residents using surface water.
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 4 violations on record, including 2 health-based violations. 1 remains unresolved.
Stinson Beach ranks #245 out of 690 cities in California for water quality, placing it mid-range 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. As a small community water system, Stinson Beach may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Stinson Beach's water
Every contaminant flagged in Stinson Beach, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.
Over Limit — EPA Action Level: 1.3 mg/L
Exceeds the EPA action level. Copper leaches from household plumbing — flush taps for 30 seconds before drinking, and consider a certified filter.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 |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 1.60 | 1.3 | mg/L | Inorganic | Over Limit |
Cities ranked by 90th-percentile lead PF PFAS in California
Cities ranked by compounds detected Cu Copper in California
Cities ranked by 90th-percentile copper
03Stinson Beach's ten-year track record
Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 4 violations on record, including 2 health-based violations. 1 remains unresolved.
9 of the last ten years were clean. The numbered years had EPA violations — red when any were health-based, amber when they were paperwork or missed-testing issues.
▼ Down 0 ppb since 1993. Latest reading: 0 ppb (2023) — 0% of the action level. Sampled at higher-risk homes (90th percentile).
▼ Down 0.20 mg/L since 1993. The latest reading (1.6 mg/L, 2010) is over the action level. Sampled at higher-risk homes (90th percentile).
04Where Stinson Beach's water comes from
Stinson Beach's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
Surface Water
Rivers, lakes, or reservoirs — more exposed to runoff, agriculture, and seasonal swings than groundwater.
Local treatment
Multi-barrier treatment: coagulation, sedimentation, filtration, and disinfection to meet EPA standards.
1 system
1 water system, operated under local government ownership.
583 people
Residents served across Stinson Beach's service area.
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 583 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| STINSON BEACH COUNTY WTR DIST | CA2110004 | 583 | Surface Water |
Water bodies near Stinson Beach
As a surface-water system, these water bodies may directly influence Stinson Beach's drinking water supply.
05Pressure on Stinson Beach's watershed
Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about.
Flood & storm history
10 federal disaster declarations on record for Marin County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
06How Stinson Beach compares
Scores for nearby California cities on one line, with the average marked.
dashed line = California average (57/100)
Stinson Beach scores 86.1/100 — above the California average of 57/100. It outscores 8 of 10 nearby cities. Full California rankings →
42.8 / 100FSan Jose, CA
28 / 100BOakland, CA
77.9 / 100FSan Diego, CA
39.7 / 100FSacramento, CA
31.2 / 100ABurlingame, CA
89.2 / 100
Compare all cities in the county — grades, violations, and contaminant data side by side.→
07What to do at home
Steps matched to what testing actually found in Stinson Beach's water — not generic advice.
Filter drinking & cooking water
Basic carbon filter for extra protection. Copper exceeds the EPA action level of 1.3 mg/L
Compare tested filters →Read your utility's annual report
Every utility must publish a yearly Consumer Confidence Report with its own testing results. It pairs well with the independent data on this page.
How to read a CCR →Watch for Stinson Beach alerts
This area has a history of flood declarations — after severe weather, watch for boil-water advisories from the utility, and check the live alerts on this page.
All water alerts →Frequently asked questions
Is Stinson Beach, CA tap water safe to drink?
Stinson Beach's water quality earned a grade of A- (86.1/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #245 out of 690 cities tested in California.
What contaminants are in Stinson Beach's water?
Lead was measured at 0.0 ppb (90th percentile). 4 violations are on record.
How is Stinson Beach'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 Stinson Beach?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Stinson Beach's water come from?
Stinson Beach's water is sourced from Surface water. The city has 1 water system serving approximately 583 residents.
What health violations has Stinson Beach's water system had?
Stinson Beach has 2 health-based violations on record. The most recent violation was recorded in April 2021. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 1 violation remains unresolved.
How does Stinson Beach's water compare to other cities?
Stinson Beach ranks #245 out of 690 cities in California (better than 64% of state cities) and #4915 out of 15382 cities nationally (68th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Stinson Beach's small water system affect quality?
Stinson Beach's system serves approximately 583 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 4 violations on record.