Public water system · CA4310022
ActiveGreat Oaks Wc Inc.
At a glance
Great Oaks Wc Inc. (PWSID CA4310022) is an active community water system in Santa Clara County, California. It reports serving 110,088 people through 21,415 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 5 violations for this system; 3 are health-based, and the most recent began in March 2015.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
110,088
Service connections
21,415
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Great Oaks Wc Inc. compare with other water systems in Santa Clara County?
By EPA's size categories, Great Oaks Wc Inc. is a very large system (more than 100,000 people). Santa Clara County has 121 active public water systems, and Great Oaks Wc Inc. is the 4th-largest of them by population served. Its population served is about 6.4 times the county average of 17,334 people per system, and accounts for 5.2% of the 2,097,447 people reported by systems filed under the county. Across California, the 7,479 active systems average 5,706 people each. Nationally, the average active community water system reports serving 6,703 people, so Great Oaks Wc Inc. is about 16 times that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. California has 2,997 active community water systems, 40% of the state's 7,479 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 6,179 California systems (83%) list groundwater as their primary source.
Who owns and regulates Great Oaks Wc Inc.?
EPA lists Great Oaks Wc Inc. as privately owned. The CA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 82 of the 121 active systems in Santa Clara County (68%) are also privately owned.
Does Great Oaks Wc Inc. have drinking water violations?
EPA's records list 5 violations for this system; 3 are health-based, and the most recent began in March 2015. The violations listed here began between September 1992 and March 2015. By type: 3 contaminant level above the legal limit and 2 monitoring and reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (4 of them). EPA lists 5 as resolved. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2015-03-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2013-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2005-08-01 | Monitoring and reportingMonitoring, Repeat Minor (TCR) · code 26 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2002-01-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1992-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
All 5 violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Great Oaks Wc Inc.: frequently asked questions
Who runs Great Oaks Wc Inc.?
Great Oaks Wc Inc. (PWSID CA4310022) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Great Oaks Wc Inc. serve?
Great Oaks Wc Inc. reports serving 110,088 people through 21,415 service connections in Santa Clara County, California.
Where does Great Oaks Wc Inc. get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Great Oaks Wc Inc. have any drinking water violations?
EPA's records list 5 violations for this system; 3 are health-based, and the most recent began in March 2015. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Great Oaks Wc Inc.'s water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. EPA's records list 5 violations for this system; 3 are health-based, and the most recent began in March 2015. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Great Oaks Wc Inc.'s water quality report?
As a community water system, Great Oaks Wc Inc. must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Santa Clara County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| San Jose Water | Santa Clara | 1,039,920 | Community | Surface water |
| City of Sunnyvale | Santa Clara | 157,566 | Community | Purchased surface water |
| City of Santa Clara | Santa Clara | 130,746 | Community | Purchased surface water |
| City of San Jose - Evg/Edv/Coy | Santa Clara | 101,265 | Community | Purchased surface water |
| City of Milpitas | Santa Clara | 81,773 | Community | Purchased surface water |
| City of Mountain View | Santa Clara | 81,501 | Community | Purchased surface water |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Great Oaks Wc Inc., PWSID CA4310022, California”, https://aquacensus.com/water-systems/california/great-oaks-wc-inc-ca4310022 (data as of October 1, 2026).