Fremont One
Community water system in San Joaquin County, California, serving 39 people from ground water. 1 rule violated in the past three years. Privately owned. System ID CA3901474.
Quarterly compliance history
2023
2024
2024
2024
2024
2025
2025
2025
2025
2026
2026
2026
2026
Still in violation
EPA data updated Oct 7, 2026
Nitrate
Nitrate (NO₃) is the most common chemical contaminant in US groundwater, entering from fertilizers, septic systems, and animal waste.
Nitrate
Nitrate (NO₃) is the most common chemical contaminant in US groundwater, entering from fertilizers, septic systems, and animal waste.
What it means: Nitrate (NO₃) is the most common chemical contaminant in US groundwater, entering from fertilizers, septic systems, and animal waste. It is odorless and tasteless — the only way to know if it's present is to test.
Health effects: Methemoglobinemia in infants under 6 months: gut bacteria convert nitrate to nitrite, which blocks oxygen transport in blood. Pregnant women should also take precautions. Chronic adult exposure at elevated levels may increase cancer risk.
Limit: 10 mg/L as nitrogen (NO₃-N)
About this contaminantAbout this data
EPA counts the rules a system was in violation of, not the individual violations; one rule can carry several in the same period. Unresolved means still in violation at EPA's latest data refresh. Measured contaminant levels are not part of this record; each system publishes them in its annual Consumer Confidence Report.
Service area from EPA's Public Water System Service Area Boundaries dataset: State Agency, verification status Not Verified. The system's location is the centre of the service area EPA publishes for the system.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The California records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.