Is Oakley, California tap water safe?
4 water systems report serving Oakley. 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.
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Contra Costa Water District
Serves 210,500 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 (2025).
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Diablo Water District
Serves 47,158 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 (2022).
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Big Oak Mobile Home Park Water
Serves 156 people · Groundwater · Full report →
No health-based violations in the last 5 years; No UCMR 5 PFAS results on file; Lead 90th percentile below the action level (2025).
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Forest Ranch Mobile Park
Serves 24 people · Groundwater · Full report →
No health-based violations in the last 5 years; 1 monitoring/reporting violation; No UCMR 5 PFAS results on file; Lead 90th percentile below the action level (2022).