Is Los Gatos, CA Tap Water Safe to Drink?
Graded D — but Copper was detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
46/100
waterverge.com Los Gatos, CA — Water Quality Report
Los Gatos's drinking water received a grade of D (46 out of 100), indicating poor water quality. The city's 16 water systems serve approximately 3,587 residents using groundwater.
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 471 violations on record, including 138 health-based violations. 66 remain unresolved.
What to know about Los Gatos's water
Los Gatos ranks #634 out of 694 cities in California for water quality, placing it among the lowest-rated in the state.
Los Gatos 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.
The system has seen 39 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Los Gatos, CA water safe to drink?
Los Gatos's drinking water has significant quality concerns based on EPA testing data. With a grade of D (46/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 16 water systems serve approximately 3,587 residents using groundwater (wells).
Recent water quality updates for Los Gatos
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Los Gatos's water quality assessment. Grade: D (46/100).
1 health-based. Contaminants: Chlorine.
Contaminants: Revised Total Coliform Rule.
1 health-based. Contaminants: Chlorine.
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.
Key contaminant findings
Based on the most recent EPA sampling data for Los Gatos's water supply.
Well within EPA limits.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
Los Gatos's water system has 471 total violations on record, including 138 health-based violations. 66 remain unresolved. 39 violations were issued in the last 5 years.
Flood & environmental risk
Santa Clara County has experienced 8 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 Guadalupe R, Saratoga C A Saratoga.
Where does Los Gatos's water come from?
Los Gatos's drinking water comes from groundwater (wells), supplied by 16 water systems serving approximately 3,587 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Guadalupe R (river), Saratoga C A Saratoga (river).
What Los Gatos residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Los Gatos'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.
Los Gatos'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 Los Gatos
Industrial polluters nearby
Reported releases to surface water by facilities near Los Gatos, ranked by pounds discharged annually.
Total reported releases to surface water: 9 lbs
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
BURKE INDUSTRIES INC SAN JOSE, CA95112 | Zinc compounds | 8 | 7.8 mi |
TTM TECHNOLOGIES N.A. LLC SANTA CLARA, CA95050 | Copper compounds | 1 | 9.3 mi |
CALIFORNIA PAPERBOARD SANTA CLARA, CA95050 | — | — | 9.3 mi |
ADVANCED RADIATION CORP SANTA CLARA, CA95050 | — | — | 9.6 mi |
STREAMLINE CIRCUITS SANTA CLARA, CA95050 | — | — | 9.4 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Superfund sites within 10 miles of Los Gatos
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.
- INTERSIL INC SIEMENS COMPONENTS7.7 mi
- LORENTZ BARREL DRUM CO8.0 mi
Source: EPA Superfund National Priorities List
Flood & disaster history
Santa Clara County has experienced 8 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 Los Gatos'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. | 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. | 1.93 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Los Gatos compares by contaminant
Explore where Los Gatos ranks among all California cities for specific contaminants.
Water source & infrastructure
Where Los Gatos's water comes from
Los Gatos'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 private ownership and serves approximately 3,587 people through 16 water systems.
Water bodies near Los Gatos
Los Gatos is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Los Gatos
| System Name | PWSID | Population | Source |
|---|---|---|---|
| COYOTE VALLEY RV RESORT | CA4300994 | 500 | GW |
| SUMMIT WEST MUTUAL WATER CO. | CA4400617 | 481 | SWP |
| VILLA DEL MONTE MWC | CA4400595 | 419 | SW |
| LAS CUMBRES MUTUAL WATER CO | CA4400631 | 402 | SW |
| ALDERCROFT HEIGHTS COUNTY WATER DISTRICT | CA4300516 | 338 | SW |
| LUPIN LODGE | CA4300716 | 300 | SW |
| RIDGE MUTUAL WATER COMPANY | CA4400618 | 213 | SWP |
| MELODY WOODS WATER COMPANY | CA4300525 | 168 | GW |
| LAKE CANYON MUTUAL WATER COMPANY | CA4300522 | 156 | SW |
| SUMMIT MUTUAL WATER COMPANY | CA4400559 | 152 | SW |
| RAINERI MUTUAL WATER COMPANY | CA4300520 | 145 | SW |
| VISTA GRANDE WATER USERS ASSOCIATION | CA4300550 | 79 | SWP |
| BRUSH AND OLD WELL MUTUAL WATER COMPANY | CA4300978 | 70 | SWP |
| LAUREL COMMUNITY LEAGUE | CA4400528 | 64 | GU |
| MIREVAL IMPROVEMENT ASSOCIATION | CA4300741 | 60 | SWP |
| MOUNTAIN SPRINGS MUTUAL WATER COMPANY | CA4300740 | 40 | SWP |
How Los Gatos compares
Full California rankings →Los Gatos's score of 46/100 is below the average of 57/100 among major California cities. It outscores 5 of 10 nearby cities.
Nearby cities
View California rankings →About Los Gatos, CA
Learn more about your water
Guides and resources related to Los Gatos's water quality findings.
Explore water quality across Santa Clara
Frequently asked questions
Is Los Gatos, CA tap water safe to drink?
Los Gatos's water quality earned a grade of D (46/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #634 out of 694 cities tested in California.
What contaminants are in Los Gatos's water?
Lead was measured at 0.0 ppb (90th percentile). 471 violations are on record.
How is Los Gatos'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 Los Gatos?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Los Gatos's water come from?
Los Gatos's water is sourced from Groundwater. The city has 16 water systems serving approximately 3,587 residents.
What health violations has Los Gatos's water system had?
Los Gatos has 138 health-based violations on record. The most recent violation was recorded in October 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 66 violations remain unresolved.
Is Los Gatos's groundwater at risk of contamination?
Los Gatos 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 471 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 Los Gatos's water compare to other cities?
Los Gatos ranks #634 out of 694 cities in California (better than 9% of state cities) and #13977 out of 15744 cities nationally (11th percentile). The grade of D reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.