Drinking water quality · 2023
· Verified
What's in San Diego, CA tap water
33 contaminants were measured in the San Diego, CA water system's 2023 annual report. Each is shown below against its federal limit — 4 sit at or above that limit.
- Reporting year
- 2023
- Contaminants measured
- 33
- Over federal limit
- 4
- Approaching the limit
- 1
- Worst contaminant
- Sodium
- Service area
- CA
PFAS — EPA UCMR5 (2023–2025)
1 PFAS compound detected in San Diego, CA
The EPA finalized the first-ever federal drinking-water limits for six PFAS compounds in April 2024. These numbers come straight from EPA's UCMR5 lab dataset — every U.S. system serving more than 3,300 people tested every PFAS sample at an entry point to its distribution system. PFAS not listed below were either tested and not detected, or not yet sampled.
Lithium
● Detected (no federal limit)near national p90 (76.59999999999991 mg/L across detecting U.S. systems)
Where your water comes from · EPA SDWIS
San Diego, CA's drinking water comes from surface water, drawn from 8 sources.
Source
- EL CAJON WELL 04
- SAN VICENTE PRODUCTION
- EL CAPITAN RESERVOIR - RAW
- MIRAMAR RESERVOIR - RAW
- + 4 more
Treatment
- MIRAMAR PLANT EFFLUENT - TREATED
- OTAY PLANT EFFLUENT - TREATED
- ALVARADO PLANT EFFLUENT - TREATED
Distribution
Also buys water from SAN DIEGO COUNTY WATER AUTHORITY.
Historical readings · EPA Six-Year Review (2012–2019)
5 contaminants historically over EPA limits in San Diego, CA
Every U.S. public water system reports compliance-monitoring data to EPA. The Six-Year Review releases the 2012–2019 window as a single dataset — here's what your system reported, year by year. Values shown are the highest detection per analyte per year, compared to the federal MCL.
| Contaminant | Worst detection | EPA limit | Years (2012–2019) |
|---|---|---|---|
GROSS BETA worst: 2017 | 30.7 mrem/yr 7.7× | 4 mrem/yr | '12'14'16'17'18'19 |
TTHM worst: 2017 | 0.126 mg/L 1.6× | 0.08 mg/L | '12'13'14'15'16'17'18'19 |
BROMATE worst: 2017 | 0.0102 mg/L 1.0× | 0.01 mg/L | '12'13'16'17'18'19 |
TCE worst: 2014 | 0.00505 mg/L 1.0× | 0.005 mg/L | '12'13'14'15'16'17'18'19 |
CHLORITE worst: 2017 | 1 mg/L 1.0× | 1 mg/L | '12'13'14'15'16'17'18'19 |
MERCURY worst: 2014 | 0.0019 mg/L 95% | 0.002 mg/L | '14 |
PCE worst: 2012 | 0.00447 mg/L 89% | 0.005 mg/L | '12'13'14'15'16'17'18'19 |
ARSENIC worst: 2013 | 0.00734 mg/L within near national p90 | 0.01 mg/L | '12'13'14'15'16'17'18'19 |
HAA5 worst: 2017 | 0.0377 mg/L within | 0.06 mg/L | '12'13'14'15'16'17'18'19 |
NITRATE worst: 2012 | 3.44 mg/L within | 10 mg/L | '12'13'14'15'16'17'18'19 |
FLUORIDE worst: 2014 | 1.02 mg/L within | 4 mg/L | '12'13'14'15'16'17'18'19 |
SELENIUM worst: 2013 | 0.00682 mg/L within | 0.05 mg/L | '13'14 |
BARIUM worst: 2016 | 0.146 mg/L within near national p90 | 2 mg/L | '14'15'16'17'18'19 |
CIS DICHLOROETHYLENE 12 worst: 2014 | 0.00101 mg/L within below national p90 | 0.07 mg/L | '13'14'15'16'17'18 |
URANIUM worst: 2018 | 0.073 ug/L within 3.4× the national p90 | 30 ug/L | '12'13'15'16'17'18'19 |
DBAA worst: 2012 | 0.0105 mg/L | — | '12'13'14'15'16'17'18'19 |
DCAA worst: 2012 | 0.0102 mg/L | — | '12'13'14'15'16'17'18'19 |
MBAA worst: 2015 | 0.00492 mg/L | — | '15'17'18'19 |
MCAA worst: 2014 | 0.00252 mg/L | — | '14'17'18 |
TCAA worst: 2012 | 0.0042 mg/L | — | '12'13'14'15'16'17'18'19 |
BROMODICHLOROMETHANE worst: 2012 | 0.0258 mg/L | — | '12'13'14'15'16'17'18'19 |
BROMOFORM worst: 2012 | 0.024 mg/L | — | '12'13'14'15'16'17'18'19 |
CHLOROFORM worst: 2012 | 0.0168 mg/L | — | '12'13'14'15'16'17'18'19 |
DIBROMOCHLOROMETHANE worst: 2012 | 0.0297 mg/L | — | '12'13'14'15'16'17'18'19 |
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| SodiumA naturally occurring salt component. | 109 mg/LAverageOtay | 1 mg/LMCL | At or above the limit |
| CopperA metal that enters water from corroding household plumbing. | 0.6 mg/L90th percentileAt the tap | 1.3 mg/LAction level | Within the limit |
| BoronA naturally occurring element from rock and soil. | 0.4 mg/LAveragePurchased Treated Water | 1 mg/LNL | Within the limit |
| ManganeseA naturally occurring metal from soil and rock. | 6.1 ug/LAverageAlvarado | 50 ug/LMCL | Within the limit |
| AluminumA common element sometimes used as a treatment coagulant. | Not detected mg/LAveragePurchased Treated Water | 0.2 mg/LMCL | Within the limit |
| Chromium, HexavalentHexavalent chromium ('chromium-6') — the more toxic form of chromium. | Not detected ug/LAveragePurchased Treated Water | 0.02 ug/LMCL | Within the limit |
| IronA naturally occurring metal common in groundwater. | Not detected ug/LAverageAlvarado | 300 ug/LMCL | Within the limit |
| LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. | Not detected ug/L90th percentileAt the tap | 15 ug/LAction level | None detected |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| AlkalinityA measure of the water's capacity to neutralize acids. | 123 mg/LAverageOtay | 5 mg/LMCL | At or above the limit |
| HardnessA measure of dissolved calcium and magnesium minerals. | 13.4AverageMiramar | 0.6MCL | At or above the limit |
| Specific ConductanceA measure of how well water conducts electricity, which tracks dissolved mineral content. | 980AverageOtay | 1600MCL | Within the limit |
| Total Dissolved SolidsTotal dissolved solids — the combined content of all dissolved minerals and salts. | 571 mg/LAverageOtay | 1000 mg/LMCL | Within the limit |
| ColorA measure of visible tint in the water. | 2AverageOtay | 15MCL | Within the limit |
| OdorA measure of detectable smell in the water. | Not detectedAverageAlvarado | 3MCL | Within the limit |
| pHA measure of how acidic or basic the water is. | 8.33AveragePurchased Treated Water | None set | Detected — no federal limit |
| TOCTotal organic carbon — a measure of organic material dissolved in the water. | 4.5 mg/LAverageOtay | None set | Detected — no federal limit |
Inorganic chemicals
Disinfection byproducts
Microbial
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Total ColiformA group of bacteria used as an indicator of overall water-system sanitation. | 0.1 %AverageCity Of San Diego Distribution System | 5 %MCL | Within the limit |
| Escherichia coli (E. coli)Escherichia coli — bacteria found in the gut of humans and animals. | 0AverageCity Of San Diego Distribution System | 0MCL | None detected |
Radionuclides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Gross AlphaGross alpha particle activity — a combined measure of alpha-emitting radioactive substances. | Not detected pCi/LAverageMiramar | 15 pCi/LMCL | Within the limit |
People also ask about San Diego, CA's water
+Is San Diego, CA tap water safe to drink in 2023?
The 2023 Consumer Confidence Report for the San Diego, CA water utility lists 4 contaminants at or above the federal limit: Sodium, Alkalinity, Hardness, and Lithium. Whether that means the water is "unsafe" depends on which contaminant, how long the exposure, and individual health factors. The table on this page shows the measured value, the federal threshold, and the regulated statistic used for compliance.
+What contaminants are in San Diego, CA tap water?
33 contaminants were measured in San Diego, CA's 2023 Consumer Confidence Report, spanning metals, physical & aggregate, and disinfection byproducts. 31 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Which contaminants exceed federal limits in San Diego, CA tap water?
4 contaminants in San Diego, CA's 2023 report sit at or above the federal limit: Sodium (109.0× the limit); Alkalinity (24.6× the limit); Hardness (22.3× the limit); Lithium (5.5× the limit). The EPA enforces these limits against the regulated reporting statistic — typically a running annual average or 90th percentile — not a one-off sample spike.
+What is the worst contaminant in San Diego, CA tap water?
The contaminant with the highest measured value relative to its federal limit in the 2023 report is Sodium, at 109.0× the federal threshold. It belongs to the metals family of contaminants.
+Are any contaminants in San Diego, CA tap water approaching the federal limit?
One contaminant is between 80% and 100% of the federal limit in this report: TTHM. Approaching means measured but not in violation — a margin that can close quickly if conditions change.
+Where does the data on this page come from?
Every value is transcribed from San Diego, CA's 2023 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is San Diego, CA's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2023 report; a new report will replace it once the utility publishes its next annual update.