Public water system · CA0105009
ActiveMountain House School
At a glance
Mountain House School (PWSID CA0105009) is an active non-transient non-community water system in Alameda County, California. It reports serving 50 people through 1 service connection. Its primary water source is purchased surface water, and EPA lists it as owned by a local government. EPA's records list 5 violations for this system; 1 is health-based, and the most recent began in January 2001.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
50
Service connections
1
Primary source
SWP
Purchased surface water
System type
NTNCWS
Non-transient non-community water system
System record
How does Mountain House School compare with other water systems in Alameda County?
By EPA's size categories, Mountain House School is a very small system (500 people or fewer). Alameda County has 27 active public water systems. Its population served is well below the county average of 83,320 people per system, and accounts for less than 0.1% of the 2,249,634 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 Mountain House School 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. Purchased surface water means the system buys surface water from another public water system rather than drawing its own. 506 California systems (6.8%) list purchased surface water as their primary source.
Who owns and regulates Mountain House School?
EPA lists Mountain House School as owned by a local government. 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. 15 of the 27 active systems in Alameda County (56%) are also owned by a local government.
Does Mountain House School have drinking water violations?
EPA's records list 5 violations for this system; 1 is health-based, and the most recent began in January 2001. The violations listed here began between August 1993 and January 2001. By type: 4 monitoring and reporting and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Total coliform bacteria (TCR) (3 of them). EPA lists 5 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 |
|---|---|---|---|---|
| 2001-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2001-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | No | Resolved |
| 1995-04-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1995-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1993-08-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
All 5 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.
Mountain House School: frequently asked questions
Who runs Mountain House School?
Mountain House School (PWSID CA0105009) is a non-transient non-community water system owned by a local government. It is regulated by the CA state drinking water program.
How many people does Mountain House School serve?
Mountain House School reports serving 50 people through 1 service connection in Alameda County, California.
Where does Mountain House School get its water?
EPA SDWIS lists this system's primary water source as purchased surface water. Purchased surface water means the system buys surface water from another public water system rather than drawing its own.
Does Mountain House School have any drinking water violations?
EPA's records list 5 violations for this system; 1 is health-based, and the most recent began in January 2001. 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 Mountain House School'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 5 violations for this system; 1 is health-based, and the most recent began in January 2001. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Mountain House School's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Mountain House School 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 Alameda County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| East Bay MUD | Alameda | 1,442,800 | Community | Surface water |
| Alameda County Water District | Alameda | 344,000 | Community | Surface water |
| City of Hayward | Alameda | 162,954 | Community | Purchased surface water |
| Dublin San Ramon Services District | Alameda | 98,776 | Community | Purchased surface water |
| City of Pleasanton | Alameda | 76,689 | Community | Purchased surface water |
| California Water Service - Livermore | Alameda | 60,414 | 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, “Mountain House School, PWSID CA0105009, California”, https://aquacensus.com/water-systems/california/mountain-house-school-ca0105009 (data as of October 1, 2026).