Is La Honda, CA Tap Water Safe to Drink?
Graded C- — but Lead and Copper were detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
56.8/100
waterverge.com La Honda, CA — Water Quality Report
La Honda's drinking water received a grade of C- (56.8 out of 100), indicating poor water quality. The city's 4 water systems serve approximately 1,418 residents using surface water.
Lead levels were measured at 25.6 ppb (90th percentile), which exceeds the EPA action level of 15 ppb. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 143 violations on record, including 9 health-based violations. 5 remain unresolved.
What to know about La Honda's water
La Honda ranks #582 out of 694 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.
Lead levels exceed the EPA action level of 15 ppb, which typically indicates aging lead service lines or lead solder in the distribution system. An NSF 53-certified filter is strongly recommended for drinking and cooking water.
As a small community water system, La Honda may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 6 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is La Honda, CA water safe to drink?
La Honda's drinking water has significant quality concerns based on EPA testing data. With a grade of C- (56.8/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 4 water systems serve approximately 1,418 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for La Honda
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into La Honda's water quality assessment. Grade: C- (56.8/100).
Contaminants: Lead and Copper Rule.
Contaminants: Surface Water Treatment 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.
1 health-based. Contaminants: Total Haloacetic Acids (HAA5).
Key contaminant findings
Based on the most recent EPA sampling data for La Honda's water supply.
Exceeds EPA action level. Lead service line replacement and point-of-use filtration recommended.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
La Honda's water system has 143 total violations on record, including 9 health-based violations. 5 remain unresolved. 6 violations were issued in the last 5 years.
Flood & environmental risk
San Mateo County has experienced 9 federally declared disasters since 1982. 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 Pescadero C Nr Pescadero, Butano C Nr Pescadero, San Gregorio C A San Gregorio, San Francisquito C A Stanford University.
Where does La Honda's water come from?
La Honda's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 4 water systems serving approximately 1,418 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment. Nearby water bodies include Pescadero C Nr Pescadero (river), Butano C Nr Pescadero (river), San Gregorio C A San Gregorio (river), San Francisquito C A Stanford University (river).
What La Honda residents can do
Recommended: NSF 53-certified pitcher or under-sink filter. This addresses the specific contaminants found in La Honda'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.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
La Honda'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 La Honda
Industrial polluters nearby
Reported releases to surface water by facilities near La Honda, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
US DOE SLAC NATIONAL ACCELERATOR LABORATORY MENLO PARK, CA94025 | — | — | 7.7 mi |
VARIAN MEDICAL SYSTEMS PALO ALTO, CA94304 | — | — | 9.4 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Superfund sites within 10 miles of La Honda
Superfund sites nearby
Federally tracked hazardous-waste sites on the EPA National Priorities List. Proximity does not necessarily indicate tap-water contamination — the connection depends on hydrology and treatment.
- HEWLETT PACKARD 620 640 PAGE MILL ROAD9.6 mi
Source: EPA Superfund National Priorities List
Flood & disaster history
San Mateo County has experienced 9 federally declared disasters since 1982. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in La Honda's water supply, we recommend the following filter types.
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. | 25.6 | 15 | ppb | Inorganic | Over Limit |
| 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. | 1.80 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how La Honda compares by contaminant
Explore where La Honda ranks among all California cities for specific contaminants.
Water source & infrastructure
Where La Honda's water comes from
La Honda'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 private ownership and serves approximately 1,418 people through 4 water systems.
Water bodies near La Honda
La Honda is located near 4 notable water bodies. As a surface water system, these water bodies may directly influence the city's drinking water supply.
Water systems serving La Honda
| System Name | PWSID | Population | Source |
|---|---|---|---|
| CUESTA LA HONDA GUILD INC | CA4110012 | 915 | SW |
| CAMP JONES GULCH | CA4100538 | 357 | GW |
| PORTOLA IMPROVEMENT ASSOCIATION MWC | CA4100555 | 90 | GU |
| REDWOOD TERRACE MUTUAL | CA4100510 | 56 | GU |
How La Honda compares
Full California rankings →La Honda's score of 56.8/100 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 →About La Honda, CA
Wikipedia →La Honda is a census-designated place (CDP) in southern San Mateo County, California, United States. The population was 979 at the 2020 census. It is located in the Santa Cruz Mountains between the Santa Clara Valley and California's Pacific coast. La Honda is near the La Honda Creek Open Space Preserve and State Route 84 on the ocean side of the Coastal Range.
Learn more about your water
Guides and resources related to La Honda's water quality findings.
Explore water quality across San Mateo
Frequently asked questions
Is La Honda, CA tap water safe to drink?
La Honda's water quality earned a grade of C- (56.8/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #582 out of 694 cities tested in California.
What contaminants are in La Honda's water?
Lead was measured at 25.6 ppb (90th percentile). 143 violations are on record.
How is La Honda'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 La Honda?
Yes — lead levels exceed the EPA action level of 15 ppb. We recommend an NSF 53-certified filter or reverse osmosis system. Based on current data, basic filtration should suffice for additional peace of mind.
Where does La Honda's water come from?
La Honda's water is sourced from Surface water. The city has 4 water systems serving approximately 1,418 residents.
What health violations has La Honda's water system had?
La Honda has 9 health-based violations on record. The most recent violation was recorded in July 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 5 violations remain unresolved.
How does La Honda's water compare to other cities?
La Honda ranks #582 out of 694 cities in California (better than 16% of state cities) and #12424 out of 15744 cities nationally (21th percentile). The grade of C- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.