Public water system · NN0403023
ActiveRound Rock NTUA
At a glance
Round Rock NTUA (PWSID NN0403023) is an active community water system in Arizona. It reports serving 876 people through 256 service connections. Its primary water source is groundwater, and EPA lists it as Native American-owned. Of the 12 most recent violations in EPA's records, 6 are health-based, and the most recent began in January 2020.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
876
Service connections
256
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Round Rock NTUA compare with other water systems in Arizona?
By EPA's size categories, Round Rock NTUA is a small system (501 to 3,300 people). 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 Round Rock NTUA 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. 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 Round Rock NTUA?
EPA lists Round Rock NTUA as Native American-owned. The NN state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act.
Does Round Rock NTUA have drinking water violations?
Of the 12 most recent violations in EPA's records, 6 are health-based, and the most recent began in January 2020. The violations listed here began between April 2012 and January 2020. By type: 6 contaminant level above the legal limit, 5 monitoring and reporting and 1 public notice, recordkeeping or other. The contaminant or rule involved most often is Combined Radium (-226 and -228) (6 of them). EPA lists 12 as resolved. 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.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2020-01-01 | Monitoring and reportingMonitoring, Routine (IDSE) · code 30 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2020-01-01 | Monitoring and reportingMonitoring, Routine (IDSE) · code 30 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2016-04-01 | Public notice, recordkeeping or otherSample Siting Plan Errors (RTCR) · code 5A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2013-10-01 | Monitoring and reportingFailure Submit IDSE/Subpart V Plan Rpt · code 35 | Stage 2 Disinfectants and Disinfection Byproducts Rulecode 0600 | No | Resolved |
| 2013-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Combined Radium (-226 and -228)code 4010 | Yes | Resolved |
| 2013-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Combined Radium (-226 and -228)code 4010 | Yes | Resolved |
| 2013-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Combined Radium (-226 and -228)code 4010 | Yes | Resolved |
| 2012-12-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2012-11-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2012-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Combined Radium (-226 and -228)code 4010 | Yes | Resolved |
| 2012-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Combined Radium (-226 and -228)code 4010 | Yes | Resolved |
| 2012-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Combined Radium (-226 and -228)code 4010 | 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.
Round Rock NTUA: frequently asked questions
Who runs Round Rock NTUA?
Round Rock NTUA (PWSID NN0403023) is a community water system Native American-owned. It is regulated by the NN state drinking water program.
How many people does Round Rock NTUA serve?
Round Rock NTUA reports serving 876 people through 256 service connections in Arizona.
Where does Round Rock NTUA 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 Round Rock NTUA have any drinking water violations?
Of the 12 most recent violations in EPA's records, 6 are health-based, and the most recent began in January 2020. 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 Round Rock NTUA'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. Of the 12 most recent violations in EPA's records, 6 are health-based, and the most recent began in January 2020. For current results, consult the system's annual water quality report, EPA ECHO, or the NN state drinking water program.
Where can I find Round Rock NTUA's water quality report?
As a community water system, Round Rock NTUA 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 Arizona
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Phoenix City of | Maricopa | 1,695,000 | Community | Surface water |
| Tucson City of | Pima | 732,906 | Community | Groundwater |
| Mesa City of | Maricopa | 466,000 | Community | Surface water |
| Gilbert, Town of | Maricopa | 247,600 | Community | Surface water |
| Chandler City of | Maricopa | 247,328 | Community | Surface water |
| Scottsdale City of | Maricopa | 241,361 | 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, “Round Rock NTUA, PWSID NN0403023, Arizona”, https://aquacensus.com/water-systems/arizona/round-rock-ntua-nn0403023 (data as of October 1, 2026).