01The verdict: is Big Sur water safe?
Big Sur's drinking water has significant quality concerns based on EPA testing data. With a grade of C+ (65.1/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 10 water systems serve approximately 2,046 residents using surface water (rivers, lakes, or reservoirs).
45 unresolved violations on record
EPA records show open compliance items for this system. Most are administrative, but unresolved items are worth watching.
See what was cited ↓Lead is well under the limit
90th-percentile lead is 0.6 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.
See the trend ↓2 violations 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 ↓Big Sur's drinking water received a grade of C+ (65.1 out of 100), indicating fair water quality. The city's 10 water systems serve approximately 2,046 residents using 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 206 violations on record, including 58 health-based violations. 45 remain unresolved.
Big Sur ranks #545 out of 690 cities in California for water quality, placing it among the lowest-rated 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, Big Sur may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Big Sur's water
Every contaminant flagged in Big Sur, 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.
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 |
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
03Big Sur'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 206 violations on record, including 58 health-based violations. 45 remain unresolved.
6 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.
▲ Up 2.5 ppb since 2008. Latest reading: 2.5 ppb (2025) — 17% of the action level. Sampled at higher-risk homes (90th percentile).
04Where Big Sur's water comes from
Big Sur'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.
10 systems
10 water systems, operated under private ownership.
2,046 people
Residents served across Big Sur'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 private ownership and serves approximately 2,046 people through 10 water systems.
| System name | PWSID | Population | Source |
|---|---|---|---|
| NEPENTHE WS | CA2701280 | 618 | Surface Water |
| POST RANCH INN WS | CA2702299 | 416 | Groundwater |
| ESALEN INSTITUTE WS | CA2701295 | 246 | Surface Water |
| VENTANA BIG SUR INN WS | CA2702328 | 193 | Surface Water |
| FERNWOOD WS | CA2702325 | 184 | Ground Water Under Influence |
| COASTLANDS MWS (POST CREEK) | CA2701279 | 129 | Surface Water |
| CLEAR RIDGE WA | CA2701898 | 123 | Ground Water Under Influence |
| RANCHO CHAPARRAL MWC | CA2701278 | 58 | Ground Water Under Influence |
| NEW CAMALDOLI HERMITAGE WS | CA2702268 | 44 | Ground Water Under Influence |
| PARTINGTON MWC | CA2701263 | 35 | Surface Water |
05How Big Sur compares
Scores for nearby California cities on one line, with the average marked.
dashed line = California average (57/100)
Big Sur scores 65.1/100 — above the California average of 57/100. It outscores 6 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.→
06What to do at home
Steps matched to what testing actually found in Big Sur's water — not generic advice.
A basic carbon filter still helps
Big Sur's water meets federal standards, but a simple carbon filter improves taste and adds a margin of safety against short-term issues.
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 Big Sur alerts
We refresh EPA data monthly and surface new violations, advisories, and boil-water notices for your county on this page.
All water alerts →Frequently asked questions
Is Big Sur, CA tap water safe to drink?
Big Sur's water quality earned a grade of C+ (65.1/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #545 out of 690 cities tested in California.
What contaminants are in Big Sur's water?
Lead was measured at 0.6 ppb (90th percentile). 206 violations are on record.
How is Big Sur'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 Big Sur?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Big Sur's water come from?
Big Sur's water is sourced from Surface water. The city has 10 water systems serving approximately 2,046 residents.
What health violations has Big Sur's water system had?
Big Sur has 58 health-based violations on record. The most recent violation was recorded in December 2023. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 45 violations remain unresolved.
How does Big Sur's water compare to other cities?
Big Sur ranks #545 out of 690 cities in California (better than 21% of state cities) and #11395 out of 15382 cities nationally (26th percentile). The grade of C+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.