Is Fremont, CA Tap Water Safe to Drink?
Graded B- — but Copper, NDMA and 1 more were detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
74.2/100
waterverge.com Fremont, CA — Water Quality Report
Fremont's drinking water received a grade of B- (74.2 out of 100), indicating fair water quality. The city's 3 water systems serve approximately 344,145 residents using surface water.
Lead levels were measured at 0.0 ppb (90th percentile), well within EPA limits. PFAS testing under UCMR 5 found no detectable forever chemicals.
The system has 28 violations on record, including 3 health-based violations. 9 remain unresolved.
What to know about Fremont's water
Fremont ranks #463 out of 694 cities in California for water quality, placing it below average 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.
Hexavalent chromium (chromium-6) was detected at 0.28 µg/L in UCMR 3 testing. While below California's 10 µg/L limit and with no federal MCL set, residents sensitive to this contaminant may consider reverse osmosis filtration.
The system has seen 8 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Fremont, CA water safe to drink?
Fremont's drinking water has significant quality concerns based on EPA testing data. With a grade of B- (74.2/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 3 water systems serve approximately 344,145 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for Fremont
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Fremont's water quality assessment. Grade: B- (74.2/100).
1 health-based. Contaminants: LEAD AND COPPER RULE REVISIONS.
Contaminants: Lead and Copper Rule.
Contaminants: Lead and Copper Rule.
Federal disaster declaration (FEMA DR-4683). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3591). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Fremont'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
Fremont's water system has 28 total violations on record, including 3 health-based violations. 9 remain unresolved. 8 violations were issued in the last 5 years.
Flood & environmental risk
Alameda County has experienced 9 federally declared disasters since 1970. 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 Coyote C Ab Hwy 237 A Milpitas, Alameda C Bl Welch C Nr Sunol, San Antonio Reservoir Nr Sunol, San Antonio C Nr Sunol, Alameda C A Sunol Water Temple A Sunol.
Where does Fremont's water come from?
Fremont's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 3 water systems serving approximately 344,145 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment. Nearby water bodies include Coyote C Ab Hwy 237 A Milpitas (river), Alameda C Bl Welch C Nr Sunol (river), San Antonio Reservoir Nr Sunol (lake), San Antonio C Nr Sunol (river), Alameda C A Sunol Water Temple A Sunol (river).
What Fremont residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Fremont'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.
Fremont'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 ↓Forever chemicals overview
National PFAS report →Violation summary
Violations & advisories
Top industrial polluters within 10 miles of Fremont
Industrial polluters nearby
Reported releases to surface water by facilities near Fremont, ranked by pounds discharged annually.
Total reported releases to surface water: 589 lbs
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
TESLA INC FREMONT, CA94538 | Zinc compounds | 560 | 0.4 mi |
TESLA INC. FREMONT, CA94538 | Nickel And Nickel Compounds | 23 | 2.0 mi |
NORTHROP GRUMMAN SYSTEMS CORP SUNNYVALE, CA94086 | Nickel And Nickel Compounds | 3 | 9.3 mi |
HILL BROTHERS CHEMICAL CO SAN JOSE, CA95131 | Ammonia | 3 | 7.9 mi |
TTM TECHNOLOGIES N.A. LLC SANTA CLARA, CA95050 | Copper compounds | 1 | 9.0 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Superfund sites within 10 miles of Fremont
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.
- SOUTH BAY ASBESTOS AREA5.0 mi
- ADVANCED MICRO DEVICES INC BUILDING 9158.3 mi
- SYNERTEK INC BUILDING 18.3 mi
- APPLIED MATERIALS8.3 mi
- MOFFETT FIELD NAVAL AIR STATION8.4 mi
+ 12 more sites
Source: EPA Superfund National Priorities List
Flood & disaster history
Alameda County has experienced 9 federally declared disasters since 1970. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Fremont'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. | 1.80 | 1.3 | mg/L | Inorganic | Over Limit |
| 11Cl-PF3OUdS | ND | HI | µg/L | PFAS | Not Detected |
| 4:2 FTS | ND | HI | µg/L | PFAS | Not Detected |
| 6:2 FTS 6:2 FTSPFAS A fluorotelomer sulfonate commonly found at sites contaminated with aqueous film-forming foam (AFFF) used in firefighting. Health EffectsPotential liver toxicity and endocrine disruption. Less studied but identified as a contaminant of concern. EPA LimitNo individual MCL (not yet regulated) Common SourcesFirefighting foam (AFFF), airports, military bases, and industrial facilities. | ND | HI | µg/L | PFAS | Not Detected |
| 8:2 FTS | ND | HI | µg/L | PFAS | Not Detected |
| 9Cl-PF3ONS | ND | HI | µg/L | PFAS | Not Detected |
| ADONA | ND | HI | µg/L | PFAS | Not Detected |
| HFPO-DA HFPO-DA (GenX)PFAS A replacement for PFOA in manufacturing, marketed as safer but still a persistent "forever chemical." Also known as GenX. Health EffectsLiver and kidney effects, reproductive toxicity, immune system effects, and potential cancer risk. EPA Limit10 ppt MCL Common SourcesFluoropolymer manufacturing (used as PFOA replacement), industrial wastewater discharge. | ND | 0.01 | µg/L | PFAS | Not Detected |
| lithium LithiumInorganic A naturally occurring alkali metal found in groundwater. Monitored under UCMR 5 to assess occurrence in drinking water. Health EffectsKidney effects at high doses. Low-level exposure effects under study; some research suggests neurological effects. EPA LimitNo MCL (monitoring only under UCMR 5) Common SourcesNatural mineral deposits, geothermal water, and industrial discharge. | ND | HI | µg/L | PFAS | Not Detected |
| NEtFOSAA | ND | HI | µg/L | PFAS | Not Detected |
| NFDHA | ND | HI | µg/L | PFAS | Not Detected |
| NMeFOSAA | ND | HI | µg/L | PFAS | Not Detected |
| PFBA PFBAPFAS One of the shortest-chain PFAS compounds. Very mobile in water and difficult to remove with standard filtration. Health EffectsThyroid effects, potential developmental toxicity. Shorter half-life in body than long-chain PFAS. EPA LimitNo individual MCL (not yet regulated) Common SourcesDegradation of longer-chain PFAS, industrial discharge, and firefighting foam. | ND | HI | µg/L | PFAS | Not Detected |
| PFBS PFBSPFAS A short-chain PFAS used as a replacement for PFOS. While it clears the body faster than long-chain PFAS, it still persists in the environment. Health EffectsThyroid effects, reproductive and developmental toxicity, kidney effects. EPA LimitPart of Hazard Index (1.0) Common SourcesIndustrial discharge, firefighting foam, and as a replacement chemical in manufacturing. | ND | HI | µg/L | PFAS | Not Detected |
| PFDA | ND | HI | µg/L | PFAS | Not Detected |
| PFDoA | ND | HI | µg/L | PFAS | Not Detected |
| PFEESA | ND | HI | µg/L | PFAS | Not Detected |
| PFHpA PFHpAPFAS A medium-chain PFAS compound found in various environmental samples. Less studied than PFOA/PFOS but still considered a contaminant of concern. Health EffectsLiver effects, potential developmental toxicity, and endocrine disruption. EPA LimitPart of Hazard Index (1.0) Common SourcesDegradation of longer-chain PFAS, industrial discharge, and contaminated water sources. | ND | HI | µg/L | PFAS | Not Detected |
| PFHpS | ND | HI | µg/L | PFAS | Not Detected |
| PFHxA PFHxAPFAS A short-chain PFAS replacement chemical widely used after manufacturers phased out longer-chain PFAS. Very commonly detected in water. Health EffectsLiver and kidney effects, potential thyroid disruption. Considered less toxic than long-chain PFAS but still persistent. EPA LimitNo individual MCL (not yet regulated) Common SourcesIndustrial processes, firefighting foam (AFFF), food packaging, and textile treatment. | ND | HI | µg/L | PFAS | Not Detected |
| PFHxS PFHxSPFAS A medium-chain PFAS found in firefighting foam and consumer products. It has a long half-life in the human body, similar to long-chain PFAS. Health EffectsImmune system effects, thyroid disruption, and potential reproductive and developmental harm. EPA LimitPart of Hazard Index (1.0) Common SourcesFirefighting foam (AFFF), waterproof textiles, food packaging, and industrial discharge. | ND | HI | µg/L | PFAS | Not Detected |
| PFMBA | ND | HI | µg/L | PFAS | Not Detected |
| PFMPA | ND | HI | µg/L | PFAS | Not Detected |
| PFNA PFNAPFAS A long-chain PFAS compound used in manufacturing fluoropolymers. It bioaccumulates in the body and is very persistent in the environment. Health EffectsDevelopmental effects, liver toxicity, immune suppression, and potential cancer risk. EPA LimitPart of Hazard Index (1.0) Common SourcesFluoropolymer manufacturing, industrial emissions, and contaminated water sources. | ND | HI | µg/L | PFAS | Not Detected |
| PFOA PFOAPFAS A long-chain PFAS ("forever chemical") once widely used in nonstick coatings and firefighting foam. It persists in the body and environment for years. Health EffectsLinked to kidney and testicular cancer, thyroid disease, elevated cholesterol, and reproductive issues. EPA Limit4.0 ppt MCL Common SourcesIndustrial discharge, firefighting foam (AFFF), nonstick cookware manufacturing, and contaminated groundwater. | ND | 0.004 | µg/L | PFAS | Not Detected |
| PFOS PFOSPFAS A long-chain PFAS compound historically used in stain-resistant coatings and firefighting foam. One of the most studied and persistent PFAS chemicals. Health EffectsLiver damage, immune system suppression, thyroid disruption, increased cholesterol, and potential cancer risk. EPA Limit4.0 ppt MCL Common SourcesFirefighting foam (AFFF), industrial sites, stain-resistant fabric treatments, and contaminated groundwater. | ND | 0.004 | µg/L | PFAS | Not Detected |
| PFPeA PFPeAPFAS A short-chain PFAS compound commonly detected in drinking water. One of the most frequently found PFAS in UCMR 5 monitoring. Health EffectsLess studied than PFOA/PFOS. Potential liver and thyroid effects. Research is ongoing. EPA LimitNo individual MCL (not yet regulated) Common SourcesIndustrial discharge, firefighting foam degradation, and consumer products. | ND | HI | µg/L | PFAS | Not Detected |
| PFPeS | ND | HI | µg/L | PFAS | Not Detected |
| PFTA | ND | HI | µg/L | PFAS | Not Detected |
| PFTrDA | ND | HI | µg/L | PFAS | Not Detected |
| PFUnA | ND | HI | µg/L | PFAS | Not Detected |
Lead level trend (90th percentile)
Copper level (90th percentile)
Latest reading: 1.600 mg/L (1992)
EPA action level: 1.3 mg/L
See how Fremont compares by contaminant
Explore where Fremont ranks among all California cities for specific contaminants.
Water source & infrastructure
Where Fremont's water comes from
Fremont'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 local government ownership and serves approximately 344,145 people through 3 water systems.
Water bodies near Fremont
Fremont is located near 5 notable water bodies. As a surface water system, these water bodies may directly influence the city's drinking water supply.
Water systems serving Fremont
| System Name | PWSID | Population | Source |
|---|---|---|---|
| ALAMEDA COUNTY WATER DISTRICT | CA0110001 | 344,000 | SW |
| MARINA MOBILE MANOR | CA0707608 | 75 | GW |
| HIDDEN HARBOR MARINA & RVP | CA5200526 | 70 | GW |
How Fremont compares
Full California rankings →Fremont's score of 74.2/100 is above the average of 57/100 among major California cities. It outscores 7 of 10 nearby cities.
Nearby cities
View California rankings →About Fremont, CA
Wikipedia →Fremont is a city in Alameda County, California, United States. Located in the East Bay region of the Bay Area, Fremont has a population of 230,504 as of 2020, making it the fourth most populous city in the Bay Area, behind San Jose, San Francisco, and Oakland. It is the closest East Bay city to the high-tech Silicon Valley network of businesses, and has a strong tech industry presence. The city's largest employer is a Tesla manufacturing plant, employing 25,000 people as of 2024.
Learn more about your water
Guides and resources related to Fremont's water quality findings.
Explore water quality across Alameda
Frequently asked questions
Is Fremont, CA tap water safe to drink?
Fremont's water quality earned a grade of B- (74.2/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #463 out of 694 cities tested in California.
What contaminants are in Fremont's water?
Lead was measured at 0.0 ppb (90th percentile). No PFAS compounds were detected. 28 violations are on record.
How is Fremont'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 Fremont?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Fremont's water come from?
Fremont's water is sourced from Surface water. The city has 3 water systems serving approximately 344,145 residents.
What health violations has Fremont's water system had?
Fremont has 3 health-based violations on record. The most recent violation was recorded in October 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 9 violations remain unresolved.
How does Fremont's water compare to other cities?
Fremont ranks #463 out of 694 cities in California (better than 33% of state cities) and #9897 out of 15744 cities nationally (37th percentile). The grade of B- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.