Public water system · CA4000770
ActiveHorizon Lane Water Supply
At a glance
Horizon Lane Water Supply (PWSID CA4000770) is an active non-transient non-community water system in San Luis Obispo County, California. It reports serving 32 people through 1 service connection. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list one violation for this system; it is health-based, and the most recent began in February 2003.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
32
Service connections
1
Primary source
GW
Groundwater
System type
NTNCWS
Non-transient non-community water system
System record
How does Horizon Lane Water Supply compare with other water systems in San Luis Obispo County?
By EPA's size categories, Horizon Lane Water Supply is a very small system (500 people or fewer). San Luis Obispo County has 171 active public water systems. Its population served is well below the county average of 2,038 people per system, and accounts for less than 0.1% of the 348,510 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 Horizon Lane Water Supply 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 Horizon Lane Water Supply?
EPA lists Horizon Lane Water Supply 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. 130 of the 171 active systems in San Luis Obispo County (76%) are also privately owned.
Does Horizon Lane Water Supply have drinking water violations?
EPA's records list one violation for this system; it is health-based, and the most recent began in February 2003. By type: 1 contaminant level above the legal limit. The contaminant or rule involved is Total coliform bacteria (TCR). 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 |
|---|---|---|---|---|
| 2003-02-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | 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.
Horizon Lane Water Supply: frequently asked questions
Who runs Horizon Lane Water Supply?
Horizon Lane Water Supply (PWSID CA4000770) is a non-transient non-community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Horizon Lane Water Supply serve?
Horizon Lane Water Supply reports serving 32 people through 1 service connection in San Luis Obispo County, California.
Where does Horizon Lane Water Supply 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 Horizon Lane Water Supply have any drinking water violations?
EPA's records list one violation for this system; it is health-based, and the most recent began in February 2003. 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 Horizon Lane Water Supply'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 health-based, and the most recent began in February 2003. For current results, consult EPA ECHO, or the CA state drinking water program.
Where can I find Horizon Lane Water Supply's water quality report?
The annual Consumer Confidence Report requirement applies to community water systems. Horizon Lane Water Supply 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 San Luis Obispo County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Santa Margarita Recreation Area | San Luis Obispo | 50,001 | Transient non-community | Groundwater |
| San Luis Obispo Water Department | San Luis Obispo | 47,788 | Community | Surface water |
| City of Paso Robles Water Division | San Luis Obispo | 31,176 | Community | Surface water |
| Atascadero Mutual Water Co | San Luis Obispo | 30,618 | Community | Groundwater |
| City of Arroyo Grande Utilities Division | San Luis Obispo | 17,963 | Community | Purchased surface water |
| California Mens Colony | San Luis Obispo | 15,000 | Community | 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, “Horizon Lane Water Supply, PWSID CA4000770, California”, https://aquacensus.com/water-systems/california/horizon-lane-water-supply-ca4000770 (data as of October 1, 2026).