Los Angeles
CA

Is Los Angeles, CA Tap Water Safe to Drink?

Los Angeles, CA tap water has a qualified safety status. It meets most federal drinking water standards, but lithium levels detected across all 106 ZIP codes served exceed the EPA's 10 µg/L health benchmark, reaching as high as 80.2 µg/L in some samples. PFAS compounds were also detected, though at or below current reporting thresholds. If you are pregnant, nursing, or have an infant at home, extra caution is warranted.

16Water systems
106ZIP codes
100%ZIPs above EPA guideline
Metro areaLos Angeles-Long Beach-Anaheim, CA
Latest data2025-10-16

Where Does Los Angeles Get Its Water?

Los Angeles draws its drinking water from a mix of local groundwater wells and imported surface water. The Los Angeles Department of Water and Power is the city's dominant utility, serving the vast majority of residents across the metro area. Several smaller utilities also operate in specific neighborhoods and communities, including Golden State Water Company serving areas such as Culver City, Florence/Graham, Southwest Los Angeles, and Willowbrook, as well as Liberty Utilities serving the Compton area and Las Virgenes Municipal Water District in the western edges of the service area.

The most prominent treatment facility is the Los Angeles Aqueduct Filtration Plant, one of the largest surface water treatment plants in the country. The Westlake Filtration Plant and the Foothill Water Treatment Plant are also part of the treatment infrastructure, along with the Dalton Plant, Converse Plant, Doty Plant, Ballona Plant, Nadeau Plant, and several well-head treatment facilities throughout the region.

Groundwater is drawn from a network of wells spread across the Los Angeles Basin and supplemented by imported water from Northern California and the Colorado River through the Metropolitan Water District interconnections. The River Supply Conduit and various MWD intertie connections are key conveyance points that blend imported and local water before treatment and distribution.

How Is Los Angeles Tap Water Treated?

Water in Los Angeles goes through several layers of treatment depending on its source. Surface water receives conventional treatment including coagulation, direct filtration, slow sand filtration, and granular activated carbon to reduce organic compounds and improve taste. Groundwater from individual wells is often treated on-site with ion exchange, membrane filtration, or biological treatment before entering the distribution system.

Disinfection methods vary across the system. Utilities use free chlorine, chloramines, and ozone at different points in the treatment process to kill bacteria and viruses and to maintain a residual disinfectant throughout the pipes that carry water to your tap. The Mockingbird Chloramination Station is one noted facility in this network. Ozone is used at certain plants as an additional disinfection and oxidation step.

Some well sites use additional specialized treatment such as air stripping, pressure sand filtration, and other technologies tailored to the specific groundwater chemistry at that location. This layered, site-specific approach reflects the complexity of managing water quality across a region as large and geologically varied as Los Angeles.

What's in Los Angeles Tap Water?

The biggest concern in recent EPA testing is lithium. Samples taken as recently as October 2025 detected lithium at levels up to 80.2 micrograms per liter (µg/L), which is eight times the EPA's health benchmark of 10 µg/L. Lithium was detected across all 106 ZIP codes in the dataset, and every one of those ZIPs had readings above that benchmark. This is the primary driver of the higher-concern rating for Los Angeles tap water.

Several PFAS compounds, a class of synthetic chemicals sometimes called forever chemicals, were also detected in testing. These include PFTrDA, PFBA, 8:2 FTS, and 6:2 FTS, each measured at 0.005 to 0.007 µg/L. No established federal enforceable limit currently applies specifically to most of these compounds individually, and the detected values were at or near the reporting threshold, meaning actual concentrations may be lower.

Lithium in drinking water typically originates from natural geological sources, as it occurs naturally in certain rock and soil formations. PFAS compounds generally enter water supplies from industrial activity, firefighting foam use, or consumer product manufacturing. The presence of both in Los Angeles water reflects the region's complex mix of natural groundwater chemistry and historical industrial land use.

ContaminantPeak detectedEPA guidelineZIPs detectedStatus
lithium 80.2 µg/L 10 µg/L 106 ZIPs Above guideline
PFTrDA 0.007 µg/L — 0 ZIPs Within guideline
PFBA 0.005 µg/L — 0 ZIPs Within guideline
8:2 FTS 0.005 µg/L — 0 ZIPs Within guideline
6:2 FTS 0.005 µg/L — 0 ZIPs Within guideline

Health Risk Profile for Los Angeles

The lithium benchmark EPA uses, 10 µg/L, is a health reference level rather than an enforceable federal maximum. Los Angeles samples peaked at 80.2 µg/L, and all 106 ZIP codes showed readings above that reference level. Ongoing research links chronic high lithium exposure in drinking water to potential effects on thyroid function and fetal development, though the science is still developing and no federal maximum contaminant level has been set.

Infants fed with formula mixed using tap water, pregnant individuals, and people with kidney or thyroid conditions may face higher risk from elevated lithium, since these groups are more sensitive to mineral imbalances. PFAS compounds detected at low levels are also of concern for pregnant individuals and infants, as some PFAS have been associated with developmental and immune effects at sustained exposures.

For most adults, a certified point-of-use filter is the most practical step you can take. Look for filters certified under NSF/ANSI standards, which is an independent third-party certification program that verifies a filter actually removes what it claims to. For lithium and heavy metals, an NSF/ANSI 58 certified reverse osmosis filter is the most effective option. For PFAS removal, look for NSF/ANSI 58 or NSF/ANSI P473 certification. A filter with NSF/ANSI 42 certification will improve taste and reduce chlorine but will not address lithium or PFAS.

It is worth keeping in mind that the lithium benchmark is not a legal limit, and the EPA has not concluded that the detected levels cause specific health outcomes in the general adult population. PFAS detections were at the very edge of the testing threshold. The concern is real enough to warrant filtered water for vulnerable groups, but this does not mean the water is unsafe for general household use for most healthy adults.

Best Broad-Spectrum Filters for This Water Profile

This city profile includes PFAS detections, chlorine disinfection, and other dissolved contaminants. Reverse osmosis (RO) systems certified under NSF/ANSI 58 provide broad reduction coverage; for PFAS specifically, confirm NSF/ANSI P473 or equivalent PFAS reduction certification.

Waterdrop G3P600 Reverse Osmosis System
Under-sink RO system

8-stage tankless RO system certified to NSF/ANSI 58, reduces 1,000+ contaminants including PFAS, lead, arsenic, fluoride, and nitrates.

See recommendations matched to your exact address: choose your ZIP code below.

Frequently Asked Questions about Los Angeles Tap Water

Is Los Angeles tap water safe to drink?

Los Angeles tap water meets most federal drinking water standards, but lithium has been detected across all ZIP codes at levels above the EPA's health benchmark of 10 µg/L, with a peak of 80.2 µg/L. PFAS compounds were also detected at low levels. For most healthy adults the risk is limited, but pregnant individuals, infants, and those with kidney or thyroid conditions should consider using a certified filter.

What contaminants are in Los Angeles tap water?

The top concern is lithium, detected at up to 80.2 µg/L versus an EPA health benchmark of 10 µg/L, present in all 106 ZIP codes tested. PFAS compounds including PFTrDA, PFBA, 8:2 FTS, and 6:2 FTS were also detected, each at 0.005 to 0.007 µg/L, at or near reporting thresholds. Chloramines and chlorine are used as disinfectants and may affect taste and odor.

Where does Los Angeles get its drinking water?

Los Angeles sources water from local groundwater wells throughout the basin and from imported surface water delivered through Metropolitan Water District connections from Northern California and the Colorado River. The Los Angeles Department of Water and Power is the primary utility. Key treatment facilities include the Los Angeles Aqueduct Filtration Plant, the Westlake Filtration Plant, and the Foothill Water Treatment Plant, along with numerous well-head treatment sites.

Do I need a water filter in Los Angeles?

A filter is a reasonable precaution given the elevated lithium readings and the presence of PFAS compounds. For lithium, a reverse osmosis filter certified to NSF/ANSI 58 is the most effective option. For PFAS, look for NSF/ANSI 58 or NSF/ANSI P473 certification. NSF/ANSI is an independent third-party label that confirms a filter performs as claimed. A basic pitcher filter with only NSF/ANSI 42 certification will not remove lithium or PFAS.

How often is Los Angeles tap water tested?

Los Angeles water systems are tested regularly under federal and state rules. The most recent EPA samples in this dataset were collected in October 2025. The federal UCMR5 monitoring program, which targets emerging contaminants like PFAS and lithium, requires utilities to test all customers and report results, adding a layer of testing beyond the routine annual requirements.

What is the best water filter for Los Angeles?

Given lithium above the EPA benchmark and PFAS detections, a reverse osmosis system certified to NSF/ANSI 58 is the most effective choice. It addresses both lithium and PFAS. If PFAS is your primary concern, also confirm the filter carries NSF/ANSI P473 certification. Under-sink reverse osmosis units are more effective than pitcher-style filters for these contaminants. Replace filters on schedule, since an overdue filter can stop performing as certified.

Tap water reports by ZIP in Los Angeles

Water utilities serving Los Angeles, CA

Service area boundaries are approximate and based on state filings or modeled estimates. Contact your utility to confirm exact service at a specific address.

Modeled boundaries are shown with a dashed outline.

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