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EPA ID CA1910067 · checked 16 Oct 2026

Los Angeles tap water: what EPA testing found

Los Angeles Department of Water and Power (EPA record: LOS ANGELES-CITY, DEPT. OF WATER & POWER) serves 3,875,566 people in CA from surface water.

What the data shows

  • Lithium above EPA’s screening level (there is no legal limit)

    Highest result 100 µg/L; EPA’s health reference level for screening is 10 µg/L.

    What fits: EPA has no lithium limit, and no NSF/ANSI standard has a lithium reduction claim, so no home filter is certified for lithium.

  • Treatment-technique violation (turbidity or filtration)

    1 health-based violation since 2016, the latest starting 2018-01-01.

    What fits: These are treatment-technique rules for the plant (turbidity and filtration). The utility fixes them; follow its public notices, including any boil-water advisory.

PFAS and lithium (EPA UCMR 5)

480 results from 4 sampling points, 26 Dec 2023 to 11 Sep 2024. 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 CA1910067). Limits: EPA PFAS rule.

ContaminantDetected inHighest resultAverageEPA limit
PFOA0 of 16not detected0 ng/L4 ng/L
PFOS0 of 16not detected0 ng/L4 ng/L
PFHxS0 of 16not detected0 ng/L10 ng/L*
PFNA0 of 16not detected0 ng/L10 ng/L*
HFPO-DA0 of 16not detected0 ng/L10 ng/L*
Lithium16 of 16100 µg/L58.3 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

Period beganContaminant or ruleViolationMeasuredStatus
1 Jan 2018Long Term 2 Enhanced Surface Water Treatment RuleTreatment Technique (SWTR and GWR)–Returned to Compliance (22 Jan 2018)

Source: EPA SDWIS via Envirofacts and the ECHO report for CA1910067, retrieved 16 Oct 2026.

Hardness

13.8 grains per gallon (highest plant or source figure of 6, 2025; varies by area), from the utility’s water report checked 16 Oct 2026. Size a softener for this water.

Plant, source or areaServesGrains per gallon
Los Angeles Aqueduct Filtration PlantSan Fernando Valley, Central LA, Western LA6.02 (5.61–6.84)
Northern Combined WellsSan Fernando Valley6.73 (4.56–8.83)
Southern Combined WellsCentral LA6.78 (4.85–9.3)
MWD Weymouth PlantHarbor/Eastern LA13.7 (11.1–16.4)
MWD Diemer PlantHarbor/Eastern LA13.8 (11.2–16.4)
MWD Jensen PlantSan Fernando Valley, Harbor/Eastern LA8.19 (8.01–8.3)

From the same report. Which plant or source serves an address depends on where it is; the utility’s report explains its areas.

109 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

Los Angeles, North Hollywood, Northridge, Van Nuys, Beverly Hills, Woodland Hills, Burbank, Canoga Park, Culver City, Encino, Gardena, Inglewood, San Pedro, Santa Clarita, Santa Monica, Sherman Oaks, Torrance, Calabasas, Chatsworth, Granada Hills, Harbor City, La Crescenta, Lomita, Malibu, Marina Del Rey, Mission Hills, North Hills, Pacific Palisades, Pacoima, Panorama City, Playa Del Rey, Playa Vista, Porter Ranch, Rancho Palos Verdes, Reseda, San Fernando, Studio City, Sun Valley, Sunland, Sylmar, Tarzana, Tujunga, Universal City, Valley Village, Venice, West Hills, West Hollywood, Wilmington, Winnetka.

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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.