Is El Cajon, CA tap water safe?
The short answer
None of the 4 utilities serving El Cajon has a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and California’s records.
Helix Water District, 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 26 ppb, above EPA’s health benchmark. Health goals are stricter than legal limits and are not enforced.
The water from Helix Water District is hard to very hard depending on the source, 130 to 353 mg/L (7.6 to 20.6 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 El Cajon’s ZIP codes, from EPA’s estimates.
- Open report
Helix Water District
California · serves 277,918 people · about 52,700 in El Cajon
3 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 26 ppb, above EPA’s health benchmark. Hardness: hard to very hard depending on the source, 130 to 353 mg/L (7.6 to 20.6 grains per gallon).
No health-based violations since 2016
- Open report
Padre Dam MWD
California · serves 93,980 people · about 4,100 in El Cajon
1 result above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 47 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Otay Water District
California · serves 242,155 people · about 730 in El Cajon
1 result above EPA’s health benchmark. The worst: Lithium at 28.9 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Sycuan
California · serves 12,350 people · about 410 in El Cajon
1 result above the limit’s level with no violation recorded, 1 result above the health goal and 1 result above EPA’s health benchmark. The worst: Uranium at 31.1 ppb, above the limit’s level, no violation.
No 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 Helix Water District’s water, which serves the most people here. Another utility’s report names what handles its own results.
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Countertop reverse osmosis
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 4, 2026
Certified for: Nitrate, Arsenic
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: Nitrate, Arsenic
Culligan 10-Cup Pitcher with ZeroWater Technology (ZEROP10)
Pitcher
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 401checked Oct. 9, 2026
Certified for: Nitrate
Water testing near El Cajon
The 3 labs California certifies closest to El Cajon, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Environmental Laboratory Network, Inc.
San Diego, CA · about 13 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, radioactivity
Analytical Environmental Lab, LLC
San Diego, CA · about 14 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, disinfection byproducts
EMSL Analytical, Inc.
San Diego, CA · about 14 miles
Certified for bacteria
Which ZIP codes are in El Cajon: 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 El Cajon
Other towns in San Diego County with a page of their own.
What to do next
- Read Helix Water District’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