Public water system · CA4100551
ActiveMarchi Central Farm
At a glance
Marchi Central Farm (PWSID CA4100551) is an active community water system in San Mateo County, California. It reports serving 50 people through 10 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, 2 are health-based, and the most recent began in January 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
50
Service connections
10
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Marchi Central Farm compare with other water systems in San Mateo County?
By EPA's size categories, Marchi Central Farm is a very small system (500 people or fewer). San Mateo County has 51 active public water systems. Its population served is well below the county average of 15,363 people per system, and accounts for less than 0.1% of the 783,522 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 Marchi Central Farm 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. 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 Marchi Central Farm?
EPA lists Marchi Central Farm 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. 27 of the 51 active systems in San Mateo County (53%) are also privately owned.
Does Marchi Central Farm have drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in January 2024. The violations listed here began between July 1993 and January 2024. By type: 8 monitoring and reporting, 2 contaminant level above the legal limit and 2 public notice, recordkeeping or other. The contaminant or rule involved most often is Antimony (4 of them). EPA lists 12 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 |
|---|---|---|---|---|
| 2024-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Antimonycode 1074 | Yes | Resolved |
| 2023-11-15 | Monitoring and reportingMonitoring, Source Water (GWR) · code 34 | E. colicode 3014 | No | Resolved |
| 2023-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Antimonycode 1074 | No | Resolved |
| 2021-01-01 | Monitoring and reportingMonitoring, Check/Repeat/Confirmation · code 04 | Antimonycode 1074 | No | Resolved |
| 2021-01-01 | Public notice, recordkeeping or otherNotification, State · code 05 | Antimonycode 1074 | No | Resolved |
| 2008-09-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2006-06-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2003-09-01 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2003-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1996-05-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1995-10-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1993-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | 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.
Marchi Central Farm: frequently asked questions
Who runs Marchi Central Farm?
Marchi Central Farm (PWSID CA4100551) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Marchi Central Farm serve?
Marchi Central Farm reports serving 50 people through 10 service connections in San Mateo County, California.
Where does Marchi Central Farm 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 Marchi Central Farm have any drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in January 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 Marchi Central Farm'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, 2 are health-based, and the most recent began in January 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 Marchi Central Farm's water quality report?
As a community water system, Marchi Central Farm 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 Mateo County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| City of Daly City | San Mateo | 104,901 | Community | Purchased surface water |
| California Water Service - San Mateo | San Mateo | 102,348 | Community | Purchased surface water |
| City of Redwood City | San Mateo | 92,819 | Community | Purchased surface water |
| California Water Service-S San Francisco | San Mateo | 64,146 | Community | Purchased surface water |
| California Water Service - Bear Gulch | San Mateo | 61,431 | Community | Surface water |
| City of San Bruno | San Mateo | 42,631 | 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, “Marchi Central Farm, PWSID CA4100551, California”, https://aquacensus.com/water-systems/california/marchi-central-farm-ca4100551 (data as of October 1, 2026).