Is San Marcos, California tap water safe?
2 water systems report serving San Marcos. Your water depends on which one serves your address. Check your bill if unsure. This list is matched from the ZIP codes in this place, so it may include nearby systems.
A
Vista Irrigation District
Serves 134,501 people · Surface water · Full report →
No health-based violations in the last 5 years; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2024).
A
Vallecitos WD
Serves 114,700 people · Surface water · Full report →
No health-based violations in the last 5 years; 1 monitoring/reporting violation; 1 not yet resolved; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2021).