San Diego Public Utilities · Blended local reservoir and imported supplies, including Colorado River and State Water Project water
San Diego, CA tap water quality
San Diego's tap water scores 86 out of 100 on published data, which puts it among the better-performing large systems in the country. EPA's UCMR 5 monitoring found no PFAS; lead measured 0 ppb at the 90th percentile against a 15 ppb action level.
Every figure, with its benchmark
Subscores run from 100 at the health benchmark to 0 at the legal limit. The city score is the weighted average of the 4 inputs published for this system.
| Measure | Result | Health benchmark | Legal limit | Subscore | Source |
|---|---|---|---|---|---|
| Lead | 0 ppb 2023 | 1 | 15 | 100 | EPA SDWIS |
| TTHMs | 55 ppb | 15 | 80 | 38 | Utility report |
| HAA5 | 15 ppb | 15 | 60 | 100 | Utility report |
| PFAS | none detected | non-detect | any | 100 | EPA UCMR 5 |
Is there PFAS in San Diego's water?
No PFAS were detected in San Diego's water during EPA's UCMR 5 monitoring. That programme tests for 29 individual PFAS compounds at reporting limits in the low parts-per-trillion, so a non-detect here is a meaningful result rather than an absence of testing.
How much lead is in San Diego's tap water?
San Diego's most recent lead 90th-percentile result is 0 ppb. That means nine in ten sampled homes measured at or below that level, and it is a summary figure, not the maximum any single household saw. The federal action level is 15 ppb, but that is a trigger for utility action, not a health threshold: no level of lead exposure is considered safe (EPA, CDC), and lead almost always enters through household plumbing and service lines rather than the treatment plant.
Is San Diego tap water safe to drink?
San Diego's water meets federal legal standards on the measures its utility reports. We score it 86 out of 100 against health-based guidance, which is stricter than the legal minimum by design. Those are two different questions, and most coverage collapses them: a supply can be entirely lawful and still carry readings above the level health researchers would prefer. This score answers the second question, and the table above shows exactly which measure moved it.
Has San Diego's water been in violation?
EPA's compliance record shows 33 violations for this system, 2 of them health-based, none of them since 2020. A health-based violation means a contaminant exceeded a legal limit or required treatment was not delivered. The rules most often cited here: Coliform (TCR) (2). Most recent entry: 2019.
Context matters when reading these. Large systems accumulate more violations simply by having more sampling points and more years on record, and a violation from a decade ago says little about water leaving the plant today. What is worth attention is a recent pattern rather than a single old entry.
What can you do about it?
If lead is the concern here, the fix is almost never the treatment plant: it's the service line and the plumbing inside the building. Running the tap for thirty seconds after long stagnation, using cold water for drinking and cooking, and asking your utility whether your address has a lead service line are all free. A filter certified to NSF/ANSI 53 for lead is the next step. If PFAS is the concern, NSF/ANSI 53 does not cover it: look for NSF/ANSI 58 reverse osmosis or a filter specifically certified under NSF/ANSI 53 for PFOA and PFOS reduction.
Compare San Diego with the rest
Fifty of the largest US systems, scored the same way, every figure cited.