Is Carson, CA tap water safe?
The short answer
1 of the 4 utilities serving Carson has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and California’s records: Los Angeles - City, Dept. of Water & Power.
California Water Service Co. - Dominguez, which serves the most people here, has 3 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 64.7 ppb, above EPA’s health benchmark. Health goals are stricter than legal limits and are not enforced.
The water from California Water Service Co. - Dominguez is soft to very hard depending on the source, 48 to 1250 mg/L (2.8 to 73.1 grains per gallon). How California’s water compares.
A town can be served by more than one utility, and some homes are on private wells. The name on your water bill tells you which is yours, and your ZIP code narrows it down. They are listed by how many people each serves in Carson’s ZIP codes, from EPA’s estimates.
- Open report
California Water Service Co. - Dominguez
California · serves 149,490 people · about 82,700 in Carson
3 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 64.7 ppb, above EPA’s health benchmark. Hardness: soft to very hard depending on the source, 48 to 1250 mg/L (2.8 to 73.1 grains per gallon).
No health-based violations since 2016
- Open report
Long Beach Utilities Department
California · serves 466,772 people · about 15,000 in Carson
3 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 54 ppb, above EPA’s health benchmark. Hardness: soft to very hard depending on the source, 11 to 280 mg/L (0.6 to 16.4 grains per gallon).
No health-based violations since 2016
- Open report
Gswc - Southwest
California · serves 277,740 people · about 10,000 in Carson
3 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 51.3 ppb, above EPA’s health benchmark. Hardness: moderately hard to very hard depending on the source, 120 to 280 mg/L (7 to 16.4 grains per gallon).
No health-based violations since 2016
- Open report
Los Angeles - City, Dept. of Water & Power
California · serves 3.9 million people · about 1,500 in Carson
4 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 100 ppb, above EPA’s health benchmark. Hardness: moderately hard to very hard depending on the source, 94 to 544 mg/L (5.5 to 31.8 grains per gallon).
2 health-based violations since 2016
What handles it
Each of these is certified, on a certifier’s listing, for a result above a line in California Water Service Co. - Dominguez’s water, which serves the most people here. Another utility’s report names what handles its own results.
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Aquasana SmartFlow Reverse Osmosis (AQ-SFRO2)
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Lead, Arsenic
Brondell Capella RC250 Reverse Osmosis System
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Lead, Arsenic
Water testing near Carson
The 3 labs California certifies closest to Carson, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
JK BioScience Inc.
Rancho Dominguez, CA · about 1 mile
Certified for bacteria, lead and copper, metals
SGS Forensic Laboratories
Carson, CA · about 3 miles
Certified for metals
Applied Microbiological Services (AMS)
Long Beach, CA · about 5 miles
Certified for bacteria
Which ZIP codes are in Carson: Census 2020 relationship files. Which utilities serve them, and how many people: EPA SDWIS and EPA’s service area map. Each utility’s results: EPA UCMR 5, EPA SDWIS, and EPA’s and the state’s compliance monitoring, as its report lists them. How they are measured: methodology. Certified labs: California State Water Resources Control Board, ELAP accredited laboratories and their fields of accreditation; distances from the Census 2020 ZIP code tabulation area gazetteer.
Near Carson
Other towns in Los Angeles County with a page of their own.
What to do next
- Read California Water Service Co. - Dominguez’s full reportEvery result with its dates, the violations, and the certification claim that handles each finding.Open the report
- About LithiumWhat it does to health, where it comes from, and the certification claim that addresses it.About Lithium
- On a private well?No utility tests a well. A certified lab test is the first step.How to test well water