Public water system · AZ0410003
ActiveArizona Water Co - Ajo
At a glance
Arizona Water Co - Ajo (PWSID AZ0410003) is an active community water system in Pima County, Arizona. It reports serving 2,100 people through 750 service connections. Its primary water source is purchased groundwater, and EPA lists it as under public/private ownership. EPA's records list 10 violations for this system; none is health-based, and the most recent began in January 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
2,100
Service connections
750
Primary source
GWP
Purchased groundwater
System type
CWS
Community water system
System record
How does Arizona Water Co - Ajo compare with other water systems in Pima County?
By EPA's size categories, Arizona Water Co - Ajo is a small system (501 to 3,300 people). Pima County has 193 active public water systems. Its population served is about 64% below the county average of 5,896 people per system, and accounts for 0.2% of the 1,137,975 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 Arizona Water Co - Ajo is well below 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. Purchased groundwater means the system buys groundwater from another public water system rather than drawing its own. 71 Arizona systems (4%) list purchased groundwater as their primary source.
Who owns and regulates Arizona Water Co - Ajo?
EPA lists Arizona Water Co - Ajo as under public/private ownership. 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. 70 of the 193 active systems in Pima County (36%) are also under public/private ownership.
Does Arizona Water Co - Ajo have drinking water violations?
EPA's records list 10 violations for this system; none is health-based, and the most recent began in January 2026. The violations listed here began between July 2002 and January 2026. By type: 8 monitoring and reporting, 1 reporting and 1 public notice, recordkeeping or other. The contaminant or rule involved most often is Chlorine (5 of them). EPA lists 9 as resolved 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. 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 |
|---|---|---|---|---|
| 2026-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Unaddressed |
| 2020-10-01 | ReportingReport Sample Result/Fail Monitor (RTCR) · code 4B | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2019-09-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2015-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2008-11-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2007-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2006-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2005-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2005-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2002-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
All 10 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.
Arizona Water Co - Ajo: frequently asked questions
Who runs Arizona Water Co - Ajo?
Arizona Water Co - Ajo (PWSID AZ0410003) is a community water system under public/private ownership. It is regulated by the AZ state drinking water program.
How many people does Arizona Water Co - Ajo serve?
Arizona Water Co - Ajo reports serving 2,100 people through 750 service connections in Pima County, Arizona.
Where does Arizona Water Co - Ajo get its water?
EPA SDWIS lists this system's primary water source as purchased groundwater. Purchased groundwater means the system buys groundwater from another public water system rather than drawing its own.
Does Arizona Water Co - Ajo have any drinking water violations?
EPA's records list 10 violations for this system; none is health-based, and the most recent began in January 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 Arizona Water Co - Ajo'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 10 violations for this system; none is health-based, and the most recent began in January 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 Arizona Water Co - Ajo's water quality report?
As a community water system, Arizona Water Co - Ajo 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 Pima County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Tucson City of | Pima | 732,906 | Community | Groundwater |
| University of Arizona | Pima | 50,000 | Non-transient non-community | Groundwater |
| Metropolitan Dwid | Pima | 45,570 | Community | Groundwater |
| Oro Valley Water Utility | Pima | 42,316 | Community | Groundwater |
| Community Wc of Green Valley | Pima | 22,085 | Community | Groundwater |
| Usaf Davis Monthan Afb | Pima | 18,640 | Community | Groundwater |
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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, “Arizona Water Co - Ajo, PWSID AZ0410003, Arizona”, https://aquacensus.com/water-systems/arizona/arizona-water-co-ajo-az0410003 (data as of October 1, 2026).