Public water system · CA3901181
ActiveNorthwest Pipe Company
At a glance
Northwest Pipe Company (PWSID CA3901181) is an active non-transient non-community water system in San Joaquin County, California. It reports serving 82 people through 3 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 8 are health-based, and the most recent began in July 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
82
Service connections
3
Primary source
GW
Groundwater
System type
NTNCWS
Non-transient non-community water system
System record
How does Northwest Pipe Company compare with other water systems in San Joaquin County?
By EPA's size categories, Northwest Pipe Company is a very small system (500 people or fewer). San Joaquin County has 302 active public water systems. Its population served is well below the county average of 2,571 people per system, and accounts for less than 0.1% 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 non-transient non-community water system reports serving 430 people, so Northwest Pipe Company is well below that figure.
What does “non-transient non-community water system” mean?
A non-transient non-community water system regularly serves at least 25 of the same people for more than six months a year, but not where they live. Schools, factories, office buildings and hospitals with their own supply are typical examples. California has 1,466 active non-transient non-community water systems, 20% 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 Northwest Pipe Company?
EPA lists Northwest Pipe Company 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 Northwest Pipe Company have drinking water violations?
Of the 12 most recent violations in EPA's records, 8 are health-based, and the most recent began in July 2025. The violations listed here began between July 2011 and July 2025. By type: 8 contaminant level above the legal limit, 2 public notice, recordkeeping or other, 1 reporting and 1 monitoring. The contaminant or rule involved most often is Total coliform bacteria (TCR) (8 of them). EPA lists 11 as resolved and 1 as unaddressed. 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. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-07-02 | ReportingNotification, Known or Potential LSL · code 4H | Lead and Copper Rule Revisionscode 5200 | No | Unaddressed |
| 2024-07-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2014-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2014-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2014-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2013-12-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2013-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2012-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2012-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2012-02-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2011-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2011-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | 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.
Northwest Pipe Company: frequently asked questions
Who runs Northwest Pipe Company?
Northwest Pipe Company (PWSID CA3901181) is a non-transient non-community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Northwest Pipe Company serve?
Northwest Pipe Company reports serving 82 people through 3 service connections in San Joaquin County, California.
Where does Northwest Pipe Company 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 Northwest Pipe Company have any drinking water violations?
Of the 12 most recent violations in EPA's records, 8 are health-based, and the most recent began in July 2025. 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 Northwest Pipe Company'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, 8 are health-based, and the most recent began in July 2025. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Northwest Pipe Company's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Northwest Pipe Company is a non-transient non-community water system, so it is not required to publish one; like every public water system, it must notify the people it serves about violations under EPA's public notification rules.
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, “Northwest Pipe Company, PWSID CA3901181, California”, https://aquacensus.com/water-systems/california/northwest-pipe-company-ca3901181 (data as of October 1, 2026).