Stanislaus County | Public water system SAFER profile
Data date: July 31, 2026
Page 1 of 3

Stanislaus County public water systems

Status classification

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

Failing20%
At-Risk21%
Potentially At-Risk16%
Not At-Risk38%
Failing
At-Risk
Potentially At-Risk
Not At-Risk
Not Assessed
Systems
15
16
12
29
4
Population
11,807
62,260
57,914
143,432
218,819
Funding since 2017
$19M
$17M
$5M
$10M
$216M

Key figures

76
public water systems
494,232
reported population
67%
serve 500 people or fewer
$267M
reported funding since 2017

System locations

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

Each point represents one system record. Nearby or overlapping points can conceal multiple systems.

Summary

Stanislaus County has 76 public water systems in the SAFER dataset. Of these, 31 (41%) are classified as Failing or At-Risk.

Those systems report serving 74,067 people. The county profile is also shaped by small systems: 51 systems serve 500 people or fewer.

4 systems are listed as Not Assessed, serving 218,819 people, so Not Assessed should not be read as a low-risk classification.

Reported funding since 2017 totals $267M across 13 systems. Technical assistance funding totals $4M.

System counts and reported population

Not Assessed systems make up 5% of listed systems and 44% of reported population. That population sits in a few large systems outside the SAFER assessment’s scope, which generally have more capacity, so this reflects scope rather than hidden risk.

Stanislaus County | Public water system SAFER profile
Data date: July 31, 2026
Page 2 of 3

Risk profile

Risk in Stanislaus County is distributed across four dimensions. Water Quality contributes the largest share of the combined weighted risk score at 41%. Across all individual indicators, No intertie appears most often, affecting 63 of 72 assessed systems.

Water Quality
41%
of combined weighted risk
State 32% · ▲ 9 pts
Most common flagWater quality trends toward MCL
Accessibility
36%
of combined weighted risk
State 36% · – 0 pts
Most common flagNo intertie
Affordability
10%
of combined weighted risk
State 17% · ▼ 7 pts
Most common flagHousehold socioeconomic burden
TMF Capacity
13%
of combined weighted risk
State 15% · ▼ 2 pts
Most common flagTotal net annual income

Water Quality

Water Quality accounts for 41% of the county’s combined weighted risk score. Water quality trends toward MCL appears in 31 of 72 assessed systems. Sources exceeding an MCL is next, appearing in 28 of 72 assessed systems.

Each indicator was assessed for 72 systems.

Accessibility

Accessibility accounts for 36% of the county’s combined weighted risk score. No intertie appears in 63 of 72 assessed systems. Limited water sources is next, appearing in 35 of 72 assessed systems.

Indicator denominators range from 59 to 72 assessed systems.

Affordability

Affordability accounts for 10% of the county’s combined weighted risk score. Household socioeconomic burden appears in 30 of 72 assessed systems. Share of household income is next, appearing in 7 of 68 assessed systems.

Indicator denominators range from 68 to 72 assessed systems.

TMF Capacity

TMF Capacity accounts for 13% of the county’s combined weighted risk score. Total net annual income appears in 31 of 72 assessed systems. Operating ratio is next, appearing in 23 of 72 assessed systems.

Indicator denominators range from 65 to 72 assessed systems.

Stanislaus County | Public water system SAFER profile
Data date: July 31, 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 76 systems in Stanislaus County.

Status by system size

SAFER status within each population group

Among systems serving 500 people or fewer, 24 of 51 are Failing or At-Risk. The highest concentration occurs among systems serving 3,301 to 10,000, at 50%.

Economic context

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

DAC and SDAC service areas contain 49 of 76 listed systems. Within those two groups, 24 systems are Failing or At-Risk.

Conditions among Failing systems

A system can appear under more than one condition

Frequently listed primary analytes

  • 1,2,3-Trichloropropane4
  • Arsenic4
  • Combined Uranium4
  • Nitrate4

Among 15 Failing systems, 12 report primary MCL violation. The most frequently listed primary analytes are 1,2,3-Trichloropropane, Arsenic, and Combined Uranium.

Reported funding

Totals since 2017 and number of systems reporting funding

Funding since 2017 totals $267M across 13 systems. Not Assessed systems account for 81% of that total. Reported technical assistance funding adds $4M.

Key takeaways

41%

of systems are Failing or At-Risk

That represents 31 systems reporting service to 74,067 people. That is above the statewide average of 33%.

41%

of weighted risk comes from Water Quality

The most widespread individual flag is no intertie, found in 63 of 72 assessed systems. Statewide, Water Quality accounts for 32% of weighted risk.

67%

of systems serve 500 people or fewer

Small systems account for 51 of the county’s 76 listed systems. That is above the statewide average of 61%.