We read 10 results from Los Angeles-City, Dept. of Water & Power’s 2025 water quality report. No results over a legal limit; 5 above a health goal or guideline.
Serves about 3,856,043 people · Water system ID CA1910067 · Read the district’s 2025 report (opens in a new tab)
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Results from the 2025 report
Each number is copied from the district’s report and links to the page it’s printed on. Where the report lists several plants, wells or purchased water, the highest is shown.
| Contaminant | Result | Health goal | Legal limit | What it means |
|---|---|---|---|---|
| Arsenicaverage · range ND to 7 · Los Angeles Aqueduct Filtration Plant, highest of 3 sources · 2025 report, page 22 | 3.3 ppb | 0.004 ppb | 10 ppb | Above the health goal825x the health goal |
| Copper90th percentile of 105 homes tested, 0 over the action level · printed as 529 ppb · sampled 2023 · Customer taps (105 homes) · 2025 report, page 12 | 0.53 ppm | 0.3 ppm | 1.3 ppm (action level) | Above the health goal1.8x the health goal |
| Lead90th percentile of 105 homes tested, 3 over the action level · sampled 2023 · Customer taps (105 homes) · 2025 report, page 12 | 3.9 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal20x the health goal |
| Total coliform bacteriahighest month · range ND to 3.4 · Distribution system (city-wide) · 2025 report, page 23 | 3.4 % positive | 0 % positive | 5 % positive | Above the health goalThe health goal is zero |
| Total dissolved solidsaverage · range 465 to 625 · MWD Diemer Plant, highest of 6 sources · 2025 report, page 24 | 545 ppm | — | 500 ppm guideline | Above the guideline1.1x the guideline (taste, odor or stains; not a health limit) |
| Chlorideaverage · range 84 to 99 · MWD Diemer Plant, highest of 6 sources · 2025 report, page 24 | 92 ppm | — | 250 ppm guideline | Within the guideline |
| Disinfection byproducts (HAA5)highest running annual average · range 4 to 14.7 · Distribution system (city-wide) · 2025 report, page 23 | 13.4 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 15.2 to 35.2 · Distribution system (city-wide) · 2025 report, page 23 | 33.8 ppb | None set | 80 ppb | Below the legal limit |
| Fluorideaverage · range 0.2 to 0.8 · System-wide · 2025 report, page 13 | 0.7 ppm | 1 ppm | 2 ppm | Below the health goal |
| Sulfateaverage · range 146 to 218 · MWD Diemer Plant, highest of 6 sources · 2025 report, page 24 | 182 ppm | — | 250 ppm guideline | Within the guideline |
Utility results describe the whole system, measured where water enters the pipes, not your tap. Your home’s plumbing can add lead or copper. 7 numbers we weren’t sure about are held back until a person checks.
EPA testing for PFAS and lithium
EPA’s own nationwide testing (UCMR 5) found these in Los Angeles-City, Dept. of Water & Power’s water between Dec 2023 and Sep 2024. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium100 ppbFound in 16 of 16 samples · highest resultAbove EPA’s health reference level of 10 ppb (a guide, not a legal limit)
Source: EPA UCMR 5 occurrence data. The highest single result is shown; one high sample doesn’t mean every glass is that high.
What you can do
Nothing here is an emergency notice: if the district has a violation, it must tell customers directly. If you’d like to lower these at your tap, these are the treatments that remove them, and the catalog shows the models certified for each. Ranking is by certified removal; commissions never change the order.
Lead
Found: Copper, Lead
What removes it: Reverse osmosis or Certified carbon block or RO.
Bacteria and viruses
Found: Total coliform bacteria
What removes it: UV purification (and tell your utility).
Salty taste / high TDS
Found: Total dissolved solids
What removes it: Reverse osmosis.
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