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Counties → California

San Diego County, California

SDWIS compliance plate

Sheet CA073 · San Diego County 197 sys · 4,832 viol · #6/3254

VIOL-SEVERE · HEALTH-MID · RANK-TOP · PHOTO-FINISH · PFAS-MID · SRC-GW · SYS-LARGE · BOOK-FULL

  • VIOL-SEVERE 93.9% flagged
  • HEALTH-MID 33.4% health
  • RANK-TOP #6/3254
  • PHOTO-FINISH ±0.0 pp
  • PFAS-MID 30.8% detect
  • SRC-GW GW lead 82%
  • SYS-LARGE 197 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: Sierra County (+ 0 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, San Diego County ranks #6 of 3,254 counties by people served, and #2 of 58 counties in California. See methodology · corpus placement.

San Diego County standing, mid-flagged corpus third

Flagged-system rate 93.9% is in the corpus middle third (≤ 100.0% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 33.4% is health-based share above the upper third (> 24.5%) . UCMR5 detect rate 30.8% is UCMR5 detect rate in the tested-pool middle third (≤ 33.3%) . Population served ranks #6 of 3,254 · #2 of 58 in California.

Flagged-rate neighbourhood around San Diego County

Lowest/highest poles plus in-state counties nearest San Diego County on % of SDWIS systems with ≥1 violation. Full ladder: /counties.

0% 20% 40% 60% 80% 100% Alpine · lowest Riverside · near San Diego · this county Sutter · highest 70% 93.4% 93.5% 93.8% 93.9% 93.9% 97.1%

Source: EPA SDWIS (county aggregates) As of 2026-05-15

Water Systems

System Name Population Violations PFAS
San Diego, City Of 1,385,379 33 Clean
Helix Water District 277,668 0 Clean
Otay Water District 238,008 0 Clean
Sweetwater Authority 191,282 15 Detected
Oceanside, City Of 171,483 12 Clean
Escondido, City Of 137,044 2 Clean
Vista Irrigation District 132,430 17 Clean
Vallecitos WD 113,500 2 Clean
Cal-Am Water Coronado 106,000 2 Clean
Carlsbad MWD 95,158 0 Clean
Padre Dam MWD 93,859 4 Detected
Olivenhain MWD 86,458 0 Clean
Poway, City Of 49,888 4 Clean
Camp Pendleton (South) 42,219 40 Detected
San Dieguito WD 40,405 3 Detected
Ramona Municipal WD 37,047 2 Clean
Nas North Island & Nab Coronado 36,990 9 Clean
Pine Valley Border Patrol Station 36,604 3 -
Lakeside WD 35,500 14 Detected
Fallbrook PUD 35,237 1 Clean
Cuyamaca Water District 33,030 25 -
Rincon del Diablo MWD (ID-1) 30,757 7 Detected
Valley Center MWD 29,938 7 Clean
Yoga Center Mother's Kitchen 27,884 41 -
San Diego Mountain Lodge 26,641 16 -
Dhs Border Patrol Hwy 94 Checkpoint 25,083 39 -
Auerbach Farms 25,068 0 -
Rainbow Municipal WD 23,536 14 Clean
Santa Fe I.D. 21,578 1 Detected
Dhs Boulevard Border Patrol 20,270 3 -
South Bay Rod & Gun Club Inc. 18,900 55 -
Palomar Christian Conference Center 13,050 16 -
Indian Hills Camp 13,032 25 -
Camp Pendleton (North) 12,651 21 -
Lake Henshaw Resort Inc. 9,913 30 -
Palomar Observatory 4,416 21 -
Mataguay Scout Reservation 4,000 35 -
Warner Springs Ranch Resort LLC 3,972 40 -
Del Mar, City Of 3,919 10 Clean
Bandy Canyon Ranch Corp 3,564 0 -
Borrego WD 3,429 12 Clean
Rincon del Diablo MWD (ID-A) 3,275 2 -
Naval Medical Center San Diego 2,981 0 -
Pine Valley Mutual WC 2,645 21 -
Schoepe Scout Reservation at Lost Valley 2,500 41 -
Majestic Pines Community SD 1,768 13 -
Julian Community Services District 1,517 175 -
Mountain Empire High School 1,000 10 -
DE Anza Springs Resort 1,000 32 -
Rancho Pauma Mutual WC 899 26 -

Compare beyond California

Mid-flagged peers for San Diego County

Cross-state counties nearest San Diego County on flagged-system share (93.9%) and cumulative violation count (4,832). In-state neighbours stay on the compliance plate above.

Similar flagged-system rate

Nearest cross-state counties by % of SDWIS systems with at least one violation on record.

4 peers

Similar violation load

Nearest cross-state counties by cumulative SDWIS violation count (all systems in the county).

4 peers

Read our methodology · Check your water system - how this data is sourced, computed, and verified.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.