Is San Martin, CA Tap Water Safe to Drink?
Graded A-, with 5 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
89.4/100
waterverge.com San Martin, CA — Water Quality Report
San Martin's drinking water received a grade of A- (89.4 out of 100), indicating good water quality. The city's 5 water systems serve approximately 961 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 69 violations on record, including 11 health-based violations. 5 remain unresolved.
What to know about San Martin's water
San Martin ranks #159 out of 694 cities in California for water quality, placing it above average in the state.
San Martin 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.
As a small community water system, San Martin may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is San Martin, CA water safe to drink?
San Martin's drinking water has significant quality concerns based on EPA testing data. With a grade of A- (89.4/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 5 water systems serve approximately 961 residents using groundwater (wells).
Recent water quality updates for San Martin
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into San Martin's water quality assessment. Grade: A- (89.4/100).
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.
Contaminants: Lead and Copper Rule.
1 health-based. Contaminants: Coliform (TCR).
Contaminants: Coliform (TCR).
Key contaminant findings
Based on the most recent EPA sampling data for San Martin's water supply.
Well within EPA limits.
Violation history
San Martin's water system has 69 total violations on record, including 11 health-based violations. 5 remain unresolved.
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 Llagas C Nr Gilroy, Coyote C Nr Gilroy, Coyote C Bl Coyote Res Nr San Martin, Coyote C Nr Madrone, Coyote C Bl Coyote Ranch Rd Nr Coyote.
Where does San Martin's water come from?
San Martin's drinking water comes from groundwater (wells), supplied by 5 water systems serving approximately 961 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Llagas C Nr Gilroy (river), Coyote C Nr Gilroy (river), Coyote C Bl Coyote Res Nr San Martin (river), Coyote C Nr Madrone (river), Coyote C Bl Coyote Ranch Rd Nr Coyote (river).
What San Martin residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in San Martin'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.
San Martin'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 San Martin
Industrial polluters nearby
Reported releases to surface water by facilities near San Martin, ranked by pounds discharged annually.
Total reported releases to surface water: 0 lbs
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
CALSTONE GILROY-OLDCASTLE APG GILROY, CA95020 | Lead And Lead Compounds | 0 | 7.2 mi |
OLDCASTLE PRECAST INC MORGAN HILL, CA95037 | — | — | 7.8 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
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.
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 |
Lead level trend (90th percentile)
See how San Martin compares by contaminant
Explore where San Martin ranks among all California cities for specific contaminants.
Water source & infrastructure
Where San Martin's water comes from
San Martin'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 local government ownership and serves approximately 961 people through 5 water systems.
Water bodies near San Martin
San Martin is located near 5 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving San Martin
| System Name | PWSID | Population | Source |
|---|---|---|---|
| SAN MARTIN COUNTY WATER DISTRICT | CA4300542 | 627 | GW |
| SAN MARTIN FOOTHILLS WATER COMPANY | CA4300638 | 145 | GW |
| RANCHO ROBLES MUTUAL WATER COMPANY | CA4300577 | 103 | GW |
| SOUTH COUNTY RETIREMENT HOME | CA4300832 | 46 | GW |
| CHIRI SWEET WATER COMPANY | CA4300757 | 40 | GW |
How San Martin compares
Full California rankings →San Martin's score of 89.4/100 is above the average of 57/100 among major California cities. It outscores 9 of 10 nearby cities.
Nearby cities
View California rankings →About San Martin, CA
Wikipedia →San Martin or San Martín is a village and census-designated place (CDP) in Santa Clara County, California, in the southern Santa Clara Valley. Located to the south of Morgan Hill and north of Gilroy, San Martin is characterized by ranches, wineries, and orchards, as well as large estates in the foothills of the Santa Cruz Mountains. As of the 2020 census, San Martin had a population of 7,008.
Learn more about your water
Guides and resources related to San Martin's water quality findings.
Explore water quality across Santa Clara
Frequently asked questions
Is San Martin, CA tap water safe to drink?
San Martin's water quality earned a grade of A- (89.4/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #159 out of 694 cities tested in California.
What contaminants are in San Martin's water?
Lead was measured at 0.0 ppb (90th percentile). 69 violations are on record.
How is San Martin'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 San Martin?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does San Martin's water come from?
San Martin's water is sourced from Groundwater. The city has 5 water systems serving approximately 961 residents.
What health violations has San Martin's water system had?
San Martin has 11 health-based violations on record. The most recent violation was recorded in October 2019. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 5 violations remain unresolved.
Is San Martin's groundwater at risk of contamination?
San Martin 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 69 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 San Martin's water compare to other cities?
San Martin ranks #159 out of 694 cities in California (better than 77% of state cities) and #2852 out of 15744 cities nationally (82th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.