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San Diego County, CA Water Quality

Water quality data for 34 public water systems serving San Diego County, California — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 34 water systems · 56 cities
✅
Excellent — All Systems Performing Well

Water quality across the county is outstanding with minimal violations and very low lead levels.

A

San Diego County Earns a A

San Diego County: 56 communities across 34 water systems. 96.4% have no open violations.

  • Median lead where detected: 1.10 ppb
  • 21 communities with a lead detection, 34 reporting none detected
  • 4 communities with PFAS above the federal limit
  • 2 with significant inspection deficiencies
  • 96.4% of communities have no open violations
1.1 ppb
Median Lead Level
County-wide, 90th percentile
34
Water Systems
Active CWS & NTNCWS
96%
Violation-Free
No active violations on record
How we grade counties: MyWaterIQ uses EPA SDWIS enforcement data — actual MCL violations and lead test results — not the aspirational MCLG targets used by some sites. A grade reflects real compliance history, not theoretical risk. Learn more →

Cities by Water Quality

⭐ Best Performing
  • San Diego
    Not detected
    No federal limits exceeded on record
    A
  • Escondido
    1.10 ppb
    No federal limits exceeded on record
    B
  • Vista
    Not detected
    No federal limits exceeded on record
    A
  • El Cajon
    Not detected
    No federal limits exceeded on record
    A
  • San Marcos
    Not detected
    No federal limits exceeded on record
    A
⚠ Needs Attention
County Lead Level — Median 1.1 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 1.1 ppb — 7.3% of the federal action level
Systems by Lead Level
Under 5 ppb
20
5 – 10 ppb
1
No Data
35

All Cities in San Diego County

San Diego Not detected A
Escondido 1.10 ppb B
Chula Vista Not detected B
Vista Not detected A
Carlsbad Not detected B
El Cajon Not detected A
San Marcos Not detected A
Oceanside Not detected A
La Mesa Not detected A
Santee 1.10 ppb A
National City Not detected B
Poway Not detected A
Encinitas 1.10 ppb A
Fallbrook 1.00 ppb A
Lemon Grove Not detected A
Imperial Beach Not detected B
Ramona 1.70 ppb A
Spring Valley Not detected A
Casa de Oro-Mount Helix Not detected A
Coronado Not detected B
Alpine 1.10 ppb A
Bonita Not detected B
Solana Beach 1.70 ppb A
Camp Pendleton South 0.51 ppb C
Bostonia Not detected A
La Presa Not reported B
Lakeside Not detected A
San Diego Country Estates 1.70 ppb A
Valley Center 4.00 ppb B
Camp Pendleton Mainside 0.51 ppb C
Winter Gardens Not detected A
Rancho San Diego Not detected A
Eucalyptus Hills Not detected A
Lake San Marcos Not detected A
Bonsall 2.70 ppb B
Hidden Meadows 4.00 ppb B
Harbison Canyon 1.10 ppb A
Del Mar 2.61 ppb A
Borrego Springs Not detected A
Granite Hills Not detected A
Rancho Santa Fe 1.70 ppb A
Crest 1.10 ppb A
Jamul Not detected A
Fairbanks Ranch Not detected A
Harmony Grove Not detected B
Rainbow 2.70 ppb B
Pine Valley Not detected B
Julian 6.10 ppb D
Descanso Not detected B
Pala 1.00 ppb F
Campo Not detected B
Elfin Forest Not detected A
Jacumba Not detected B
Potrero Not detected B
Del Dios Not detected B
Mount Laguna 0.60 ppb C
Showing 56 cities
No active violations Active violations

About San Diego County Drinking Water

San Diego County is served by 34 water systems covering 56 communities. 96% have no open violations.

Of the communities reporting lead results, 21 recorded a detection, with a median of 1.10 ppb — 7% of the federal action level. 34 reported none detected, which means below the laboratory limit rather than an absence of lead.

4 of 56 communities have PFAS above the limits EPA set in 2024, measured as a running annual average at each sampling point. State inspectors recorded significant deficiencies at 2 of them.

Frequently Asked Questions

Is San Diego County tap water safe to drink?▼
96% of communities have no open violation. 4 of 56 have PFAS above the federal limit, which is the main open concern.
What is the lead level in San Diego County?▼
Among communities with a detection the median is 1.10 ppb, 7% of the 15 ppb action level. 34 reported none detected and 1 reported no result.
How many water systems serve San Diego County?▼
34 community water systems serve 56 communities here.
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