Fremont, CA Water Quality (ZIP 94539)

Quick Answers

Is ZIP 94539 tap water safe to drink? PFAS compounds have been detected in 94539's water at an average of 0.01 ppt across 1 compound. A certified pitcher filter or reverse osmosis system is recommended, especially for sensitive populations.

What filter should I use in 94539? A reverse osmosis system (NSF/ANSI 58) removes 90%+ of PFAS, lead, and arsenic. For smaller households, an NSF-53 certified pitcher (Clearly Filtered, ZeroWater) works. Standard Brita cartridges are not certified for PFAS.

ZIP 94539 Water Quality Summary

EPA testing has detected PFAS "forever chemicals" in the water system serving ZIP 94539 (Fremont, CA). Monitoring found a peak of 0.01 ppt across 1 system, averaging 0.01 ppt over 1 detected compound.

Contamination Level: LOW – Low contamination – PFAS detected but at lower levels; monitoring continues.

Top Detected Compounds in ZIP 94539

• PFBA: 0.01 ppt

Lead in ZIP 94539 Water

EPA Lead and Copper Rule testing recorded 13 lead samples for the system serving 94539, with a 90th-percentile high of 0.024 mg/L (above the EPA 0.015 mg/L action level). There is no safe level of lead for children; homes built before 1986 should use a certified NSF/ANSI 53 lead filter.

About the Data

Source: EPA UCMR5 monitoring (2023-2025), Lead and Copper Rule samples, and SDWIS violation records tied to the water system that serves 94539 in Fremont, CA.

Beyond water: other exposures in Fremont, CA

Drinking water is one exposure route. These are the other federal datasets that cover ZIP 94539 and Alameda County, CA.

Radon risk in Alameda County, CA

The EPA places Alameda County, CA in Zone 2 - a moderate-risk category, with a predicted average indoor radon level between 2 and 4 pCi/L. Zone maps predict the radon potential of an area from geology and existing indoor readings - they do not describe any individual home. Radon is the leading cause of lung cancer among people who have never smoked, and the only way to know your own level is a test kit.

Lead paint risk in Alameda County, CA

Census figures show 67% of homes in Alameda County, CA were built before 1980, and 26% before 1950. Lead-based paint was banned for residential use in 1978, so older housing stock is the strongest available proxy for lead-paint exposure. This is a statistic about the county's housing, not a test of any particular property - if your home predates 1980, a lead swab test is the way to check.

Air quality in Alameda County, CA

Modelled annual fine-particle pollution (PM2.5) for Alameda County, CA averages 8.4 µg/m³, within the EPA's annual PM2.5 standard of 9 µg/m³. PM2.5 is the pollution fraction small enough to reach deep into the lungs. These are CDC modelled estimates for the county as a whole, not a reading taken at this ZIP code.

Industrial releases near 94539

EPA Toxics Release Inventory data for 2023 records 6 reporting facilities within about five miles of 94539, together reporting roughly 1,692,984 pounds of on-site chemical releases that year. TRI covers facilities above federal reporting thresholds, so smaller sources are not included, and a reported release is not the same as a measured concentration in air or water.