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San Diego, CA · 1,423,069 people served · EPA data 2021–2026

Tap water quality in San Diego, California

San Diego's water systems logged 5 health-based EPA violations in 2021–2026, most recently in 2024 — most often revised total coliform rule. Health-based violations mean a federal limit or treatment standard was exceeded; check the systems below and your utility's annual report for specifics.

C-Fair
San Diego water grade: C-
Fair — our A–F grade from this city's EPA compliance record, relative to California and the nation. How we grade →
Health-based violations, 2021–20265
Revised Total Coliform Rule4
Lead And Copper Rule Revisions1
San Diego, City Of1,385,379 served
Nas North Island & Nab Coronado36,990 served
Butterfield Ranch353 served
Cottonwood Ridge Manufactured Housing Co205 served
California quality rank#25 / 51 (83.7/100)
California avg hardness200 PPM (very hard)
Want to know what's actually in your San Diego water?

Averages describe states, not your faucet. A certified home water test screens for lead, nitrates, bacteria and dozens of other contaminants — the same categories EPA regulates.

Test your water at home

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San Diego tap water FAQ

Is tap water safe to drink in San Diego?

San Diego's systems logged 5 health-based violations in 2021–2026, most commonly revised total coliform rule. A violation is a red flag for a period of time, not a permanent condition — your utility's current Consumer Confidence Report shows today's status, and a certified home test shows what's at your tap.

Who supplies San Diego's water?

San Diego, City Of (serving about 1,385,379 people); Nas North Island & Nab Coronado (serving about 36,990 people); Butterfield Ranch (serving about 353 people); Cottonwood Ridge Manufactured Housing Co (serving about 205 people). Data: EPA Safe Drinking Water Information System, July 2026.

How hard is the water in San Diego?

City-level hardness isn't published in a single federal dataset, but California averages 200 PPM — "very hard" on the USGS scale. Your utility's water quality report lists San Diego's exact hardness, or a $10 test strip tells you in a minute. If it comes back over 120 PPM, see our water softener guidance in the purification calculator.

Do I need a water filter in San Diego?

With 5 health-based violations on record in 2021–2026, a certified filter is reasonable insurance here: reverse osmosis ($150–$1,300 installed, Angi 2026) covers lead, nitrates and PFAS at the tap. Test first ($50–$200) so you buy for what's actually present.

Want to know what's actually in your San Diego water?

Averages describe states, not your faucet. A certified home water test screens for lead, nitrates, bacteria and dozens of other contaminants — the same categories EPA regulates.

Test your water at home

We may earn a commission if you request quotes through this link. It costs you nothing and never affects the data we publish.