Public water system · CA4901093
ActiveMartinelli Ranch
At a glance
Martinelli Ranch (PWSID CA4901093) is an active non-transient non-community water system in Sonoma County, California. It reports serving 63 people through 10 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 3 violations for this system; 2 are health-based, and the most recent began in October 2005.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
63
Service connections
10
Primary source
GW
Groundwater
System type
NTNCWS
Non-transient non-community water system
System record
How does Martinelli Ranch compare with other water systems in Sonoma County?
By EPA's size categories, Martinelli Ranch is a very small system (500 people or fewer). Sonoma County has 441 active public water systems. Its population served is well below the county average of 1,092 people per system, and accounts for less than 0.1% of the 481,435 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 Martinelli Ranch 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 Martinelli Ranch?
EPA lists Martinelli Ranch 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. 371 of the 441 active systems in Sonoma County (84%) are also privately owned.
Does Martinelli Ranch have drinking water violations?
EPA's records list 3 violations for this system; 2 are health-based, and the most recent began in October 2005. The violations listed here began between April 1995 and October 2005. By type: 2 contaminant level above the legal limit and 1 monitoring and reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (3 of them). EPA lists 3 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 |
|---|---|---|---|---|
| 2005-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2005-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1995-04-01 | Monitoring and reportingMonitoring, Repeat Minor (TCR) · code 26 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
All 3 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.
Martinelli Ranch: frequently asked questions
Who runs Martinelli Ranch?
Martinelli Ranch (PWSID CA4901093) is a non-transient non-community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Martinelli Ranch serve?
Martinelli Ranch reports serving 63 people through 10 service connections in Sonoma County, California.
Where does Martinelli Ranch 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 Martinelli Ranch have any drinking water violations?
EPA's records list 3 violations for this system; 2 are health-based, and the most recent began in October 2005. 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 Martinelli Ranch'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 3 violations for this system; 2 are health-based, and the most recent began in October 2005. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Martinelli Ranch's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Martinelli Ranch 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 Sonoma County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Santa Rosa, City of | Sonoma | 175,396 | Community | Groundwater |
| Petaluma, City of | Sonoma | 60,781 | Community | Groundwater |
| Rohnert Park, City of | Sonoma | 43,821 | Community | Groundwater |
| Windsor, Town of | Sonoma | 25,561 | Community | Groundwater |
| Valley of the Moon Water District | Sonoma | 23,107 | Community | Groundwater |
| Sonoma, City of | Sonoma | 11,725 | Community | Groundwater |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “Martinelli Ranch, PWSID CA4901093, California”, https://aquacensus.com/water-systems/california/martinelli-ranch-ca4901093 (data as of October 1, 2026).