Is San Diego, CA Tap Water Safe? Quality & Contaminants

What was found in San Diego's water

The highest level seen across the city's suppliers, the EPA limit for each, and where the figure comes from.

Contaminant	Level vs EPA limit	Suppliers	Source
Nitrate	3435.2 µg/L 34% of the EPA limit 10000 µg/L	3/4	SYR4
Fluoride	1960 µg/L 49% of the EPA limit 4000 µg/L	3/4	SYR4
Chlorite	1000 µg/L 100% of the EPA limit 1000 µg/L	1/4	SYR4
Nitrate-Nitrite	620 µg/L 6.2% of the EPA limit 10000 µg/L	1/4	SYR4
Barium	146 µg/L 7.3% of the EPA limit 2000 µg/L	3/4	SYR4
TTHM	126 µg/L 158% of the EPA limit, in the worst sample — 80 µg/L	3/4	SYR4
Combined Uranium	73.01 µg/L 243% of the EPA limit, in the worst sample — 30 µg/L	3/4	SYR4
Lithium	65 µg/L No EPA limit set	2/4	UCMR-5
Chloroform	53 µg/L No EPA limit set	3/4	SYR4
Dibromochloromethane	39.9 µg/L No EPA limit set	3/4	SYR4
Bromodichloromethane	39.4 µg/L No EPA limit set	3/4	SYR4
Bromoform	38.5 µg/L No EPA limit set	3/4	SYR4
Total Haloacetic Acids (HAA5)	37.7 µg/L 63% of the EPA limit 60 µg/L	3/4	SYR4
Gross Beta Particle Activity	30.7 pCi/L No EPA limit set	2/4	SYR4
Trichloroacetic Acid	28 µg/L No EPA limit set	3/4	SYR4
Dichloroacetic Acid	23.6 µg/L No EPA limit set	3/4	SYR4
Bromate	15 µg/L 150% of the EPA limit, in the worst sample — 10 µg/L	2/4	SYR4
Dibromoacetic Acid	14.8 µg/L No EPA limit set	3/4	SYR4
Selenium	8 µg/L 16% of the EPA limit 50 µg/L	2/4	SYR4
Arsenic	7.34 µg/L 73% of the EPA limit 10 µg/L	2/4	SYR4
Monobromoacetic Acid	6.41 µg/L No EPA limit set	2/4	SYR4
Trichloroethylene	5.05 µg/L 101% of the EPA limit, in the worst sample — 5 µg/L	1/4	SYR4
Tetrachloroethylene	4.47 µg/L 89% of the EPA limit 5 µg/L	1/4	SYR4
Monochloroacetic Acid	2.52 µg/L No EPA limit set	3/4	SYR4
Mercury	1.9 µg/L 95% of the EPA limit 2 µg/L	1/4	SYR4
cis-1,2-Dichloroethylene	1.01 µg/L 1.4% of the EPA limit 70 µg/L	1/4	SYR4
Dichloromethane	0.5800 µg/L 12% of the EPA limit 5 µg/L	1/4	SYR4
Lead	0.0 mg/L 0% of the EPA limit 0.0150 mg/L	3/4	LCR

Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the single worst sample on record — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately. These are the utilities' own EPA-reported results, not a city-wide average. A detection means the lab measured the substance — it isn't the same as exceeding a legal limit. Hover a source tag to see the EPA program and years behind each figure.

Water suppliers serving San Diego

Supplier	Population served
SAN DIEGO, CITY OF	1,385,379
NAS NORTH ISLAND & NAB CORONADO	36,990
BUTTERFIELD RANCH	353
SAN DIEGO COUNTY WATER AUTHORITY	0

Frequently asked questions about San Diego tap water

Is San Diego tap water safe to drink?

EPA testing detected 28 contaminants in the water serving San Diego. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.

How many water suppliers serve San Diego?

4 public water suppliers report drinking-water monitoring for San Diego, California to the EPA. Each is listed above with its population served.

What contaminants are in San Diego's water?

The contaminants EPA monitoring detected in San Diego include Nitrate, Fluoride, Chlorite, Nitrate-Nitrite, Barium. The full list, with the highest level found and the data source, is in the table above.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.