Mendocino County | Public water system SAFER profile
Data date: September 23, 2026
Page 1 of 3

Mendocino County public water systems

Failing or At-Risk
11systems
9,109people served (14% of total)
Not At-Risk or Not Assessed
35systems
43,709people served (69% of total)
includes Not Assessed systems, which are outside the SAFER assessment

Status classification

Share of listed systems, followed by the count, reported population, and funding in each status.

Failing11%
At-Risk9%
Potentially At-Risk16%
Not At-Risk60%
Failing
At-Risk
Potentially At-Risk
Not At-Risk
Not Assessed
Systems
6
5
9
33
2
Population
818
8,291
10,228
43,629
80
Funding since 2017
$0
$7M
$0
$16M
$0

Key figures

55
public water systems
63,046
reported population
76%
serve 500 people or fewer
$23M
reported funding since 2017

System locations

Points show reported system locations. They do not represent service-area boundaries.

Each point represents one system record.

Summary

Mendocino County has 55 public water systems in the SAFER dataset. Of these, 11 (20%) are classified as Failing or At-Risk.

Those systems report serving 9,109 people. The county profile is also shaped by small systems: 42 systems serve 500 people or fewer.

2 systems are Not Assessed. These fall outside the SAFER risk assessment, so they carry no classification either way.

Reported funding since 2017 totals $23M across 3 systems. Technical assistance funding totals $1M.

System counts and reported population

Failing systems make up 11% of listed systems and 1% of reported population. This status is concentrated in smaller systems, so it reaches fewer people than its system count suggests.

Mendocino County | Public water system SAFER profile
Data date: September 23, 2026
Page 2 of 3

Risk profile

Risk in Mendocino County is distributed across four dimensions. Accessibility contributes the largest share of the combined weighted risk score at 37%. Across all individual indicators, No intertie appears most often, affecting 48 of 53 assessed systems.

Water Quality
25%
of combined weighted risk
State 33% · ▼ 8 pts
Most common flagWater quality trends toward MCL
Accessibility
37%
of combined weighted risk
State 36% · ▲ 1 pts
Most common flagNo intertie
Affordability
26%
of combined weighted risk
State 17% · ▲ 8 pts
Most common flagHousehold socioeconomic burden
TMF Capacity
13%
of combined weighted risk
State 14% · ▼ 1 pts
Most common flagTotal net annual income

Water Quality

Water Quality accounts for 25% of the county’s combined weighted risk score. Water quality trends toward MCL appears in 22 of 53 assessed systems. Emerging contaminants is next, appearing in 13 of 53 assessed systems.

Each indicator was assessed for 53 systems.

Accessibility

Accessibility accounts for 37% of the county’s combined weighted risk score. No intertie appears in 48 of 53 assessed systems. Limited water sources is next, appearing in 17 of 53 assessed systems.

Indicator denominators range from 52 to 53 assessed systems.

Affordability

Affordability accounts for 26% of the county’s combined weighted risk score. Household socioeconomic burden appears in 33 of 53 assessed systems. Share of household income is next, appearing in 15 of 52 assessed systems.

Indicator denominators range from 52 to 53 assessed systems.

TMF Capacity

TMF Capacity accounts for 13% of the county’s combined weighted risk score. Total net annual income appears in 18 of 53 assessed systems. Operating ratio is next, appearing in 15 of 53 assessed systems.

Indicator denominators range from 49 to 53 assessed systems.

Mendocino County | Public water system SAFER profile
Data date: September 23, 2026
Page 3 of 3

Patterns and context

The countywide totals hide important differences among systems. The panels below show how SAFER status varies by system size and service-area economic status, what conditions appear among Failing systems, and how reported funding is distributed across the 55 systems in Mendocino County.

Status by system size

SAFER status within each population group

Among systems serving 500 people or fewer, 8 of 42 are Failing or At-Risk. The highest concentration occurs among systems serving 501 to 3,300, at 40%.

Economic context

Orange shows Failing or At-Risk systems within each service-area group

DAC and SDAC service areas contain 22 of 55 listed systems. Within those two groups, 6 systems are Failing or At-Risk.

Conditions among Failing systems

A system can appear under more than one condition

Frequently listed primary analytes

  • Fluoride1

Among 6 Failing systems, 2 report treatment technique violation. The most frequently listed primary analytes are Fluoride.

Reported funding

Totals since 2017 and number of systems reporting funding

Funding since 2017 totals $23M across 3 systems. Not At-Risk systems account for 72% of that total. Reported technical assistance funding adds $1M.

Key takeaways

20%

of systems are Failing or At-Risk

That represents 11 systems reporting service to 9,109 people. That is below the statewide average of 33%.

37%

of weighted risk comes from Accessibility

The most widespread individual flag is no intertie, found in 48 of 53 assessed systems. Statewide, Accessibility accounts for 36% of weighted risk.

76%

of systems serve 500 people or fewer

Small systems account for 42 of the county’s 55 listed systems. That is above the statewide average of 63%.