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Counties → California

Santa Clara County, California

SDWIS compliance plate

Sheet CA085 · Santa Clara County 119 sys · 2,640 viol · #18/3254

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

  • VIOL-SEVERE 91.6% flagged
  • HEALTH-MID 35.5% health
  • RANK-TOP #18/3254
  • PHOTO-FINISH ±0.1 pp
  • PFAS-MID 29.4% detect
  • SRC-GW GW lead 69%
  • SYS-MID 119 systems
  • BOOK-FULL 7/7 fields

Nearest flagged-rate peer: Madera County (+ 0.1 pp flagged-rate)

According to EPA SDWIS county population served used on /counties, Santa Clara County ranks #18 of 3,254 counties by people served, and #7 of 58 counties in California. See methodology · corpus placement.

Santa Clara County standing, lower-flagged corpus third

Flagged-system rate 91.6% is at or below the corpus lower third (≤ 92.7% flagged) across 2,973 counties with ≥3 SDWIS systems . Health-based share 35.5% is health-based share above the upper third (> 24.5%) . UCMR5 detect rate 29.4% is UCMR5 detect rate in the tested-pool middle third (≤ 33.3%) . Population served ranks #18 of 3,254 · #7 of 58 in California.

Flagged-rate neighbourhood around Santa Clara County

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

0% 20% 40% 60% 80% 100% Alpine · lowest San Bernardino · near Madera · near Sutter · highest 70% 91.4% 91.5% 91.6% 91.7% 91.9% 97.1%

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

Water Systems

System Name Population Violations PFAS
San Jose Water 1,039,920 14 Detected
City of Sunnyvale 157,566 145 Clean
City of Santa Clara 130,746 7 Clean
Great Oaks WC Inc 110,088 11 Detected
City of San Jose - Evg/Edv/Coy 101,265 6 Clean
City of Milpitas 81,773 15 Clean
City of Mountain View 81,501 17 Clean
Cwsc los Altos Suburban 69,973 7 Detected
City of Palo Alto 67,231 18 Clean
City of Gilroy 59,203 2 Detected
City of Morgan Hill 47,374 256 Detected
City of San Jose - Nsj/Alviso 45,559 10 Clean
Stanford University 35,853 8 Clean
City of Cupertino 16,336 15 Clean
Nasa Ames Research Center 16,273 4 Clean
Purissima Hills Water District 6,245 17 Clean
El Camino Hospital 3,000 5 -
Santa Clara Valley Medical Center 3,000 21 -
O'Connor Hospital 2,500 31 -
Western Digital Technologies, Inc. 2,439 15 Clean
Cal Am - West San Martin 1,173 27 -
Gavilan Joint Community College District 989 11 -
Csp Henry W. Coe State Park 898 14 -
Christopher Ranch L.L.C. 735 9 -
San Martin County Water District 627 70 -
Mt. Madonna County Park 621 1 -
Loma Prieta Jusd-Loma Prieta School 542 15 -
Gilroy Usd-Rucker School 536 9 -
Uvas Canyon County Park 509 24 -
Coyote Valley RV Resort 500 4 -
Camp Saratoga 450 5 -
Cinnabar Hills Golf Club 450 10 -
Sanborn-Skyline County Park 414 28 -
Thousand Trails - Morgan Hill 413 8 -
Monterey Mushrooms 361 21 -
Chemeketa Park Mutual Water Company 346 67 -
Aldercroft Heights County Water District 338 57 -
Joseph Grant County Park 326 11 -
Twin Valley Inc 317 129 -
New Avenue Mutual Water Company 305 7 -
Mt. Pleasant Water Users Association 300 30 -
Lupin Lodge 300 57 -
Lick Observatory-Ucsc 284 6 -
Walden West 273 30 -
Willow Heights Mansion 269 0 -
Nestldown Ranch 265 0 -
Saratoga Heights Mutual Water Company 258 16 -
Casa de Fruta Water System 250 14 -
Parkway Lakes RV Park 250 19 -
George Chiala Farms Inc 250 30 -

Compare beyond California

Lower-flagged peers for Santa Clara County

Cross-state counties nearest Santa Clara County on flagged-system share (91.6%) and cumulative violation count (2,640). 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.