Public water system · CA3910022
ActiveLittle Potato Slough Mutual
At a glance
Little Potato Slough Mutual (PWSID CA3910022) is an active community water system in San Joaquin County, California. It reports serving 1,510 people through 202 service connections. Its primary water source is surface water, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in October 2021.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
1,510
Service connections
202
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Little Potato Slough Mutual compare with other water systems in San Joaquin County?
By EPA's size categories, Little Potato Slough Mutual is a small system (501 to 3,300 people). San Joaquin County has 302 active public water systems. Its population served is about 41% below the county average of 2,571 people per system, and accounts for 0.2% of the 776,334 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 Little Potato Slough Mutual is well below 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. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 609 California systems (8.1%) list surface water as their primary source.
Who owns and regulates Little Potato Slough Mutual?
EPA lists Little Potato Slough Mutual 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. 225 of the 302 active systems in San Joaquin County (75%) are also privately owned.
Does Little Potato Slough Mutual have drinking water violations?
Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in October 2021. The violations listed here began between June 1989 and October 2021. By type: 5 contaminant level above the legal limit, 5 monitoring and reporting and 2 public notice, recordkeeping or other. The contaminant or rule involved most often is Haloacetic acids (HAA5) (4 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 |
|---|---|---|---|---|
| 2021-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2019-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2019-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2019-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2016-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2004-11-01 | Public notice, recordkeeping or otherOperations Report · code 10 | Not reported | No | Resolved |
| 2004-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2003-08-01 | Monitoring and reportingMonitoring, Repeat Minor (TCR) · code 26 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2001-03-01 | Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36 | Surface Water Treatment Rulecode 0200 | No | Resolved |
| 1999-12-01 | Monitoring and reportingMonitoring, Repeat Minor (TCR) · code 26 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1989-06-01 | Monitoring and reportingMonitoring, Regular · code 03 | Fluoridecode 1025 | No | Archived |
| 1989-06-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
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.
Little Potato Slough Mutual: frequently asked questions
Who runs Little Potato Slough Mutual?
Little Potato Slough Mutual (PWSID CA3910022) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Little Potato Slough Mutual serve?
Little Potato Slough Mutual reports serving 1,510 people through 202 service connections in San Joaquin County, California.
Where does Little Potato Slough Mutual get its water?
EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.
Does Little Potato Slough Mutual 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 October 2021. 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 Little Potato Slough Mutual'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 October 2021. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Little Potato Slough Mutual's water quality report?
As a community water system, Little Potato Slough Mutual 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 Joaquin County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| City of Stockton | San Joaquin | 191,302 | Community | Surface water |
| California Water Service - Stockton | San Joaquin | 176,266 | Community | Purchased surface water |
| Tracy, City of | San Joaquin | 96,609 | Community | Surface water |
| Manteca, City of | San Joaquin | 84,928 | Community | Purchased surface water |
| Lodi, City of | San Joaquin | 68,272 | Community | Surface water |
| City of Lathrop | San Joaquin | 35,080 | 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, “Little Potato Slough Mutual, PWSID CA3910022, California”, https://aquacensus.com/water-systems/california/little-potato-slough-mutual-ca3910022 (data as of October 1, 2026).