Public water system · CA3510001
ActiveHollister, City of
At a glance
City of Hollister (PWSID CA3510001) is an active community water system in San Benito County, California. It reports serving 26,017 people through 7,884 service connections. Its primary water source is purchased surface water, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in April 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
26,017
Service connections
7,884
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does City of Hollister compare with other water systems in San Benito County?
By EPA's size categories, City of Hollister is a large system (10,001 to 100,000 people). San Benito County has 63 active public water systems, and City of Hollister is the largest of them by population served. Its population served is about 20 times the county average of 1,312 people per system, and accounts for 31% of the 82,670 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 City of Hollister is about 3.9 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. Purchased surface water means the system buys surface water from another public water system rather than drawing its own. 506 California systems (6.8%) list purchased surface water as their primary source.
Who owns and regulates City of Hollister?
EPA lists City of Hollister as owned by a local government. 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. 11 of the 63 active systems in San Benito County (17%) are also owned by a local government.
Does City of Hollister have drinking water violations?
Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in April 2024. The violations listed here began between March 2000 and April 2024. By type: 7 monitoring and reporting and 5 contaminant level above the legal limit. The contaminant or rule involved most often is Total trihalomethanes (TTHM) (6 of them). EPA lists 10 as resolved and 2 as archived. 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. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2024-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Archived |
| 2024-04-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Archived |
| 2022-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2018-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2018-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2016-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2015-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2015-10-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2010-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2010-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Combined Uraniumcode 4006 | No | Resolved |
| 2000-03-01 | Monitoring and reportingMonitoring, Repeat Minor (TCR) · code 26 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
The 12 most recent 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.
City of Hollister: frequently asked questions
Who runs City of Hollister?
City of Hollister (PWSID CA3510001) is a community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does City of Hollister serve?
City of Hollister reports serving 26,017 people through 7,884 service connections in San Benito County, California.
Where does City of Hollister get its water?
EPA SDWIS lists this system's primary water source as purchased surface water. Purchased surface water means the system buys surface water from another public water system rather than drawing its own.
Does City of Hollister have any drinking water violations?
Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in April 2024. 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 City of Hollister'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. Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in April 2024. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find City of Hollister's water quality report?
As a community water system, City of Hollister 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 San Benito County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Sunnyslope County Water Dist | San Benito | 24,954 | Community | Purchased surface water |
| 33rd District Agricultural Association | San Benito | 9,000 | Transient non-community | Groundwater |
| San Benito High School | San Benito | 3,310 | Non-transient non-community | Groundwater |
| Aromas Water District | San Benito | 2,988 | Community | Groundwater |
| San Juan Bautista, City of | San Benito | 2,335 | Community | Groundwater |
| Pinnacles National Park-East District | San Benito | 1,811 | Transient non-community | Groundwater |
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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, “Hollister, City of, PWSID CA3510001, California”, https://aquacensus.com/water-systems/california/hollister-city-of-ca3510001 (data as of October 1, 2026).