Public water system · CA1710003
ActiveHighlands Mutual Water Company
At a glance
Highlands Mutual Water Company (PWSID CA1710003) is an active community water system in Lake County, California. It reports serving 7,772 people through 2,355 service connections. Its primary water source is surface water, and EPA lists it as privately owned. EPA's records list 6 violations for this system; 5 are health-based, and the most recent began in April 2021.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
7,772
Service connections
2,355
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Highlands Mutual Water Company compare with other water systems in Lake County?
By EPA's size categories, Highlands Mutual Water Company is a medium system (3,301 to 10,000 people). Lake County has 81 active public water systems, and Highlands Mutual Water Company is the largest of them by population served. Its population served is about 8.7 times the county average of 895 people per system, and accounts for 11% of the 72,454 people reported by systems filed under the county. Across California, the 7,479 active systems average 5,706 people each. Nationally, the average active community water system reports serving 6,703 people, so Highlands Mutual Water Company is about 16% above that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. California has 2,997 active community water systems, 40% of the state's 7,479 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 609 California systems (8.1%) list surface water as their primary source.
Who owns and regulates Highlands Mutual Water Company?
EPA lists Highlands Mutual Water Company 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. 60 of the 81 active systems in Lake County (74%) are also privately owned.
Does Highlands Mutual Water Company have drinking water violations?
EPA's records list 6 violations for this system; 5 are health-based, and the most recent began in April 2021. The violations listed here began between October 2015 and April 2021. By type: 5 contaminant level above the legal limit and 1 monitoring and reporting. The contaminant or rule involved most often is Haloacetic acids (HAA5) (4 of them). EPA lists 6 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 |
|---|---|---|---|---|
| 2021-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2021-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2019-10-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2019-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2019-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Haloacetic acids (HAA5)code 2456 | Yes | Resolved |
| 2015-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
All 6 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.
Highlands Mutual Water Company: frequently asked questions
Who runs Highlands Mutual Water Company?
Highlands Mutual Water Company (PWSID CA1710003) is a community water system privately owned. It is regulated by the CA state drinking water program.
How many people does Highlands Mutual Water Company serve?
Highlands Mutual Water Company reports serving 7,772 people through 2,355 service connections in Lake County, California.
Where does Highlands Mutual Water Company get its water?
EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.
Does Highlands Mutual Water Company have any drinking water violations?
EPA's records list 6 violations for this system; 5 are health-based, and the most recent began in April 2021. 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 Highlands Mutual Water Company'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 6 violations for this system; 5 are health-based, and the most recent began in April 2021. For current results, consult the system's annual water quality report, EPA ECHO, or the CA state drinking water program.
Where can I find Highlands Mutual Water Company's water quality report?
As a community water system, Highlands Mutual Water Company must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Lake County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Hidden Valley Lake Csd | Lake | 6,235 | Community | Groundwater |
| Konocti County Water District | Lake | 5,928 | Community | Surface water |
| Lakeport, City of | Lake | 4,762 | Community | Surface water |
| Golden State Water Co.-Clearlake System | Lake | 4,644 | Community | Surface water |
| Mt. Konocti Mutual Water Company | Lake | 4,360 | Community | Surface water |
| Kelseyville Co Waterworks District 3 | Lake | 4,102 | 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, “Highlands Mutual Water Company, PWSID CA1710003, California”, https://aquacensus.com/water-systems/california/highlands-mutual-water-company-ca1710003 (data as of October 1, 2026).