Public water system · AZ0412004
ActiveNogales City of
At a glance
City of Nogales (PWSID AZ0412004) is an active community water system in Santa Cruz County, Arizona. It reports serving 22,000 people through 5,400 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in October 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
22,000
Service connections
5,400
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does City of Nogales compare with other water systems in Santa Cruz County?
By EPA's size categories, City of Nogales is a large system (10,001 to 100,000 people). Santa Cruz County has 37 active public water systems, and City of Nogales is the largest of them by population served. Its population served is about 16 times the county average of 1,350 people per system, and accounts for 44% of the 49,946 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 Nogales is about 3.3 times 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. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 1,612 Arizona systems (91%) list groundwater as their primary source.
Who owns and regulates City of Nogales?
EPA lists City of Nogales 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. 6 of the 37 active systems in Santa Cruz County (16%) are also owned by a local government.
Does City of Nogales have drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in October 2025. The violations listed here began between October 2023 and October 2025. By type: 8 monitoring and reporting, 2 public notice, recordkeeping or other, 1 reporting and 1 required treatment not met. The contaminant or rule involved most often is Arsenic (3 of them). EPA lists 10 as resolved and 2 as archived. 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.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | No | Archived |
| 2025-07-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2025-07-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Chlorinecode 0999 | No | Resolved |
| 2025-07-01 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | No | Archived |
| 2024-12-20 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2024-10-17 | ReportingLSL Reporting · code 4G | Lead and Copper Rule Revisionscode 5200 | No | Resolved |
| 2024-10-17 | Required treatment not metLSL Inventory · code 2E | Lead and Copper Rule Revisionscode 5200 | Yes | Resolved |
| 2024-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2024-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2024-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Arseniccode 1005 | No | Resolved |
| 2024-04-28 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2023-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | 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 Nogales: frequently asked questions
Who runs City of Nogales?
City of Nogales (PWSID AZ0412004) 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 Nogales serve?
City of Nogales reports serving 22,000 people through 5,400 service connections in Santa Cruz County, Arizona.
Where does City of Nogales get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does City of Nogales have any drinking water violations?
Of the 12 most recent violations in EPA's records, one is health-based, and the most recent began in October 2025. 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 Nogales' 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, one is health-based, and the most recent began in October 2025. 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 Nogales' water quality report?
As a community water system, City of Nogales 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 Santa Cruz County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Liberty Water Rio Rico | Santa Cruz | 17,960 | Community | Groundwater |
| Valle Verde Water Company - East | Santa Cruz | 2,331 | Community | Groundwater |
| Epcor - Tubac | Santa Cruz | 2,076 | Community | Groundwater |
| Baca Float Water Company | Santa Cruz | 1,090 | Community | Groundwater |
| Patagonia Water Department | Santa Cruz | 819 | Community | Groundwater |
| Az State Pks Patagonia Lake | Santa Cruz | 564 | Transient non-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, “Nogales City of, PWSID AZ0412004, Arizona”, https://aquacensus.com/water-systems/arizona/nogales-city-of-az0412004 (data as of October 1, 2026).