Public water system · CA4901004
ActiveCalpine (West Field Office)
At a glance
Calpine (West Field Office) (PWSID CA4901004) is an active non-transient non-community water system in Sonoma County, California. It reports serving 26 people through 3 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list one violation for this system; it is not health-based, and the most recent began in July 1993.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
26
Service connections
3
Primary source
GW
Groundwater
System type
NTNCWS
Non-transient non-community water system
System record
How does Calpine (West Field Office) compare with other water systems in Sonoma County?
By EPA's size categories, Calpine (West Field Office) 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 Calpine (West Field Office) 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 Calpine (West Field Office)?
EPA lists Calpine (West Field Office) 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 Calpine (West Field Office) have drinking water violations?
EPA's records list one violation for this system; it is not health-based, and the most recent began in July 1993. By type: 1 monitoring and reporting. The contaminant or rule involved is Lead and Copper Rule. EPA lists 1 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 |
|---|---|---|---|---|
| 1993-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
The one violation in EPA's records.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.
Calpine (West Field Office): frequently asked questions
Who runs Calpine (West Field Office)?
Calpine (West Field Office) (PWSID CA4901004) is a non-transient non-community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Calpine (West Field Office) serve?
Calpine (West Field Office) reports serving 26 people through 3 service connections in Sonoma County, California.
Where does Calpine (West Field Office) 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 Calpine (West Field Office) have any drinking water violations?
EPA's records list one violation for this system; it is not health-based, and the most recent began in July 1993. 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 Calpine (West Field Office)'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 one violation for this system; it is not health-based, and the most recent began in July 1993. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Calpine (West Field Office)'s water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Calpine (West Field Office) 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 |
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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, “Calpine (West Field Office), PWSID CA4901004, California”, https://aquacensus.com/water-systems/california/calpine-west-field-office-ca4901004 (data as of October 1, 2026).