Public water system · AZ0403026
ActiveWilliams City of
At a glance
City of Williams (PWSID AZ0403026) is an active community water system in Coconino County, Arizona. It reports serving 3,145 people through 1,883 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in February 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
3,145
Service connections
1,883
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does City of Williams compare with other water systems in Coconino County?
By EPA's size categories, City of Williams is a small system (501 to 3,300 people). Coconino County has 114 active public water systems. Its population served is about twice the county average of 1,573 people per system, and accounts for 1.8% of the 179,316 people reported by systems filed under the county. Across Arizona, the 1,769 active systems average 4,369 people each. Nationally, the average active community water system reports serving 6,703 people, so City of Williams is about half of 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. Arizona has 936 active community water systems, 53% of the state's 1,769 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 61 Arizona systems (3.4%) list surface water as their primary source.
Who owns and regulates City of Williams?
EPA lists City of Williams as owned by a local government. The AZ state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 8 of the 114 active systems in Coconino County (7%) are also owned by a local government.
Does City of Williams have drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in February 2026. The violations listed here began between April 2023 and February 2026. By type: 6 monitoring and reporting, 2 contaminant level above the legal limit, 2 public notice, recordkeeping or other and 2 required treatment not met. The contaminant or rule involved most often is Arsenic (3 of them). EPA lists 7 as resolved, 4 as archived and 1 as unaddressed. 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. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status. Unaddressed means the violation is not resolved or archived and is not yet covered by formal enforcement.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2026-02-01 | Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36 | Surface Water Treatment Rulecode 0200 | No | Archived |
| 2026-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | No | Archived |
| 2026-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Archived |
| 2026-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Unaddressed |
| 2025-12-01 | Monitoring and reportingMonitoring, Turbidity (Enhanced SWTR) · code 38 | Interim Enhanced Surface Water Treatment Rulecode 0300 | No | Resolved |
| 2025-12-01 | Monitoring and reportingMonitoring of Treatment (SWTR-Filter) · code 36 | Surface Water Treatment Rulecode 0200 | No | Resolved |
| 2025-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Arseniccode 1005 | Yes | Archived |
| 2025-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2025-05-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2023-10-02 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2023-05-01 | Required treatment not metMonthly Turbidity Exceed (Enhanced SWTR) · code 44 | Interim Enhanced Surface Water Treatment Rulecode 0300 | Yes | Resolved |
| 2023-04-01 | Required treatment not metMonthly Turbidity Exceed (Enhanced SWTR) · code 44 | Interim Enhanced Surface Water Treatment Rulecode 0300 | Yes | Resolved |
The 12 most recent 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.
City of Williams: frequently asked questions
Who runs City of Williams?
City of Williams (PWSID AZ0403026) is a community water system owned by a local government. It is regulated by the AZ state drinking water program.
How many people does City of Williams serve?
City of Williams reports serving 3,145 people through 1,883 service connections in Coconino County, Arizona.
Where does City of Williams 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 City of Williams have any drinking water violations?
Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in February 2026. 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 City of Williams' 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. Of the 12 most recent violations in EPA's records, 4 are health-based, and the most recent began in February 2026. For current results, consult the system's annual water quality report, EPA ECHO, or the AZ state drinking water program.
Where can I find City of Williams' water quality report?
As a community water system, City of Williams 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 Coconino County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Flagstaff City of | Coconino | 79,796 | Community | Surface water |
| Grand Canyon National Park | Coconino | 16,590 | Community | Groundwater |
| Arizona Water Co - Sedona | Coconino | 12,104 | Community | Groundwater |
| Doney Park Water | Coconino | 8,996 | Community | Groundwater |
| Arizona Water Co - Pinewood | Coconino | 8,089 | Community | Groundwater |
| Page City of | Coconino | 7,420 | 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, “Williams City of, PWSID AZ0403026, Arizona”, https://aquacensus.com/water-systems/arizona/williams-city-of-az0403026 (data as of October 1, 2026).