Is San Diego tap water safe to drink?
In the latest results, every contaminant we list with a single federal limit was below that limit or action level. Lead was reported to EPA as 0 ppb at the 90th percentile, below the 15 ppb action level. EPA’s goal for lead is zero. Lithium was found above EPA’s health reference level (10 ppb), a screening value that is not an enforceable limit. EPA lists no health-based violations in the last 10 years (8 monitoring, reporting or notice records). See how US tap water compares nationally.
What’s in San Diego tap water
Latest results from San Diego PUD’s 2025 report and EPA records. One row per contaminant, with the type of limit in the limit column.
| Contaminant | Result | Limit | Sampled | Source |
|---|---|---|---|---|
| LeadComes mostly from home plumbing, not from the source water. | 0 ppb 90th percentile reported to EPA as 0; previous round (2021–2023): 0 ppb | 15 ppbAction level · goal 0Drops to 10 ppb on Nov 1, 2027 (Lead and Copper Rule Improvements). | 2024–2026 | EPA SDWIS record, CA3710020 |
| PFOA and PFOS (PFAS)Two “forever chemicals” with a federal limit. | Not detected 16 samples at 4 entry points; none at or above the reporting level (4 ppt) | 4.0 ppt eachLegal limit (MCL) · goal 0Utilities must comply from 2029; EPA proposed 2031 in May 2026. | Jan 2023 – Dec 2023 | EPA UCMR 5 final occurrence data (Aug 2026 release) |
| Total trihalomethanesByproducts of disinfection. | 55 ppb Highest locational running annual average; range 8.6–87.0 | 80 ppbLegal limit (MCL) | 2025 | City of San Diego 2025 Annual Drinking Water Quality Report |
| Haloacetic acids (HAA5)Byproducts of disinfection. | 15 ppb Highest locational running annual average; range 1.3–21.2 | 60 ppbLegal limit (MCL) | 2025 | City of San Diego 2025 Annual Drinking Water Quality Report |
| Chloramine (as total chlorine)Disinfectant kept in the pipes on purpose. | 1.75 mg/L Average; range ND–3.80 | 4.0 mg/LDisinfectant limit (MRDL) · goal 4 | 2025 | City of San Diego 2025 Annual Drinking Water Quality Report |
| LithiumUnregulated; EPA is collecting national data. | Up to 65 ppb Found in 15 of 16 samples at 4 entry points; range 16–65 | 10 ppbEPA health reference levelA health reference level is a screening value, not an enforceable limit. | Jan 2023 – Dec 2023 | EPA UCMR 5 final occurrence data (Aug 2026 release) |
ppb = parts per billion (µg/L), ppt = parts per trillion (ng/L). The bar shows the result against the limit (black line). Limits: EPA drinking water regulations, PFAS rule, Lead and Copper Rule Improvements. “Not detected” means below the lab’s reporting level, not zero.
EPA violations
EPA’s SDWIS database lists 12 violation records for San Diego PUD since 2011, none of them health-based. All have a return-to-compliance date.
Not listed: 4 older monitoring, reporting or notice records (2011–2014), none health-based.
Shown: health-based violations and everything from the last 10 years. Source: EPA SDWIS record, CA3710020, retrieved Oct 13, 2026.
How hard is San Diego water?
San Diego PUD reports hardness separately for each of its treatment plants and for water it buys from the San Diego County Water Authority.
| Purchased water (San Diego County Water Authority) | 145 mg/L · 8.5 gpg (54.4–232) |
| Alvarado treatment plant | 237 mg/L · 13.9 gpg (203–270) |
| Miramar treatment plant | 242 mg/L · 14.2 gpg (200–285) |
| Otay treatment plant | 243 mg/L · 14.2 gpg (201–271) |
The utility’s figures cover the whole system. To test the hardness at your tap, strips or a drop kit take minutes.
Classes: USGS (0–60 mg/L soft, 61–120 moderately hard, 121–180 hard, above 180 very hard). 1 gpg = 17.1 mg/L as calcium carbonate. Source: City of San Diego 2025 Annual Drinking Water Quality Report.
What to do with these numbers
Only what the data above points to.
Hard water in parts of San Diego
Above 120 mg/L (7.1 gpg) USGS calls water hard. Hardness has no federal health limit, but it leaves scale in kettles, water heaters and on fixtures. Filters for lead or chloramine do not reduce it. A water softener at the main line does.
Whole-house systems compared →Chloramine taste and smell
San Diego PUD disinfects with chloramine on purpose, below the 4.0 mg/L limit. If you dislike the taste, look for a filter certified to NSF/ANSI 42 for chloramine. For home dialysis and aquariums it must be reduced first.
Certified to reduce chloramine.
Under-sink filters compared →Test your own water
San Diego PUD’s numbers come from its own sampling sites. A certified lab test of your faucet shows lead and copper from your plumbing and the chloramine level at your tap. How to test your own tap for lead, starting with your water utility.
All water tests compared →