Public water system · CA5500026
ActiveDeloro Valley Water System
At a glance
Deloro Valley Water System (PWSID CA5500026) is an active transient non-community water system in Tuolumne County, California. It reports serving 40 people through 48 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, 6 are health-based, and the most recent began in November 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
40
Service connections
48
Primary source
GW
Groundwater
System type
TNCWS
Transient non-community water system
System record
How does Deloro Valley Water System compare with other water systems in Tuolumne County?
By EPA's size categories, Deloro Valley Water System is a very small system (500 people or fewer). Tuolumne County has 117 active public water systems. Its population served is well below the county average of 706 people per system, and accounts for less than 0.1% of the 82,611 people reported by systems filed under the county. Across California, the 7,479 active systems average 5,706 people each. Nationally, the average active transient non-community water system reports serving 144 people, so Deloro Valley Water System is well below that figure.
What does “transient non-community water system” mean?
A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. California has 3,016 active transient non-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 Deloro Valley Water System?
EPA lists Deloro Valley Water System 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. 75 of the 117 active systems in Tuolumne County (64%) are also privately owned.
Does Deloro Valley Water System have drinking water violations?
Of the 12 most recent violations in EPA's records, 6 are health-based, and the most recent began in November 2025. The violations listed here began between October 1982 and November 2025. By type: 6 contaminant level above the legal limit, 4 public notice, recordkeeping or other, 1 monitoring and 1 monitoring and reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (4 of them). EPA lists 6 as archived and 6 as resolved. 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. 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 |
|---|---|---|---|---|
| 2025-11-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, E. coli (RTCR) · code 1A | Revised Total Coliform Rulecode 8000 | Yes | Archived |
| 2025-04-01 | MonitoringMonitoring, Lab Certification/Method Error (RTCR) · code 3D | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2025-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Archived |
| 2017-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, E. coli (RTCR) · code 1A | Revised Total Coliform Rulecode 8000 | Yes | Resolved |
| 2014-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 2004-06-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Acute (TCR) · code 21 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1997-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1997-02-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1983-07-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1983-04-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1983-01-01 | Public notice, recordkeeping or otherNotification, Public · code 06 | Not reported | No | Archived |
| 1982-10-01 | 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.
Deloro Valley Water System: frequently asked questions
Who runs Deloro Valley Water System?
Deloro Valley Water System (PWSID CA5500026) is a transient non-community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Deloro Valley Water System serve?
Deloro Valley Water System reports serving 40 people through 48 service connections in Tuolumne County, California.
Where does Deloro Valley Water System 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 Deloro Valley Water System have any drinking water violations?
Of the 12 most recent violations in EPA's records, 6 are health-based, and the most recent began in November 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 Deloro Valley Water System'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, 6 are health-based, and the most recent began in November 2025. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Deloro Valley Water System's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Deloro Valley Water System is a 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 Tuolumne County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Tud - Upper Basin Water System | Tuolumne | 13,280 | Community | Surface water |
| Tud - Sonora/Jamestown Water System | Tuolumne | 11,054 | Community | Surface water |
| Tud - Columbia Water System | Tuolumne | 5,463 | Community | Surface water |
| Peppery Bar and Grill, the | Tuolumne | 4,500 | Transient non-community | Groundwater |
| Cdcr - Sierra Conservation Center | Tuolumne | 3,571 | Community | Surface water |
| Groveland Community Serv Dist | Tuolumne | 3,400 | Community | Surface water |
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, “Deloro Valley Water System, PWSID CA5500026, California”, https://aquacensus.com/water-systems/california/deloro-valley-water-system-ca5500026 (data as of October 1, 2026).