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EPA ID CA0110005 · checked 16 Oct 2026

Oakland and the East Bay tap water: what EPA testing found

East Bay Municipal Utility District (EBMUD) (EPA record: EAST BAY MUD) serves 1,468,000 people in CA from surface water. It also sells water to other utilities.

What the data shows

PFAS and lithium (EPA UCMR 5)

626 results from 6 sampling points, 4 Apr 2023 to 16 Dec 2025. Averages count results below EPA’s reporting level as zero, as the PFAS rule does. Every number links to EPA’s UCMR 5 Data Finder (search PWSID CA0110005). Limits: EPA PFAS rule.

ContaminantDetected inHighest resultAverageEPA limit
PFOA0 of 21not detected0 ng/L4 ng/L
PFOS0 of 21not detected0 ng/L4 ng/L
PFHxS0 of 21not detected0 ng/L10 ng/L*
PFNA0 of 21not detected0 ng/L10 ng/L*
HFPO-DA0 of 21not detected0 ng/L10 ng/L*
PFBA2 of 215.2 ng/L0.49 ng/Lnone
PFHxA2 of 213.5 ng/L0.33 ng/Lnone
Lithium0 of 21not detected0 µg/Lnone (screening level 10 µg/L)

* PFHxS, PFNA and HFPO-DA limits (and the PFAS hazard index) are in the rule, but EPA proposed on 20 May 2026 to rescind them; not final as of 16 Oct 2026. UCMR 5 results are screening data, not compliance results: compliance uses quarterly running averages from 2029. Source file: EPA UCMR 5 occurrence data (dated 15 Oct 2026).

Health-based violations since 2016

None in EPA’s SDWIS data.

Source: EPA SDWIS via Envirofacts and the ECHO report for CA0110005, retrieved 16 Oct 2026.

Hardness

9.4 grains per gallon (top of the range 0.8-9.4 gpg, 2025; varies by area), from the utility’s water report checked 16 Oct 2026. Size a softener for this water.

60 of this system’s ZIP codes are placed in a plant’s service area using the utility’s service-area map (checked 17 Oct 2026); the ZIP checker shows your ZIP code’s figure.

Places and ZIP codes served

Oakland, Berkeley, Hayward, Walnut Creek, Richmond, San Leandro, Alameda, Castro Valley, Danville, San Ramon, Alamo, Albany, Crockett, Diablo, Dublin, El Cerrito, El Sobrante, Emeryville, Hercules, Lafayette, Martinez, Moraga, Orinda, Pinole, Pleasant Hill, Port Costa, Rodeo, San Lorenzo, San Pablo.

94501 94502 94506 94507 94523 94525 94526 94528 94530 94541 94542 94544 94545 94546 94547 94549 94552 94553 94556 94563 94564 94568 94569 94572 94577 94578 94579 94580 94582 94583 94595 94596 94597 94598 94601 94602 94603 94605 94606 94607 94608 94609 94610 94611 94612 94613 94618 94619 94621 94702 94703 94704 94705 94706 94707 94708 94709 94710 94720 94801 94803 94804 94805 94806

ZIP codes the system reported to EPA for UCMR 5; place names from GeoNames (CC BY 4.0). A ZIP code can be split between systems.