Public water system · VA6153675
ActiveMcb Quantico - Mainside
At a glance
Mcb Quantico - Mainside (PWSID VA6153675) is an active community water system in Prince William County, Virginia. It reports serving 19,000 people through 1,314 service connections. Its primary water source is surface water, and EPA lists it as owned by the federal government. Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in January 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
19,000
Service connections
1,314
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does Mcb Quantico - Mainside compare with other water systems in Prince William County?
By EPA's size categories, Mcb Quantico - Mainside is a large system (10,001 to 100,000 people). Prince William County has 36 active public water systems, and Mcb Quantico - Mainside is the 4th-largest of them by population served. Its population served is about 65% above the county average of 11,503 people per system, and accounts for 4.6% of the 414,096 people reported by systems filed under the county. Across Virginia, the 2,420 active systems average 3,122 people each. Nationally, the average active community water system reports serving 6,703 people, so Mcb Quantico - Mainside is about 183% above 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. Virginia has 844 active community water systems, 35% of the state's 2,420 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 110 Virginia systems (4.5%) list surface water as their primary source.
Who owns and regulates Mcb Quantico - Mainside?
EPA lists Mcb Quantico - Mainside as owned by the federal government. The VA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 4 of the 36 active systems in Prince William County (11%) are also owned by the federal government.
Does Mcb Quantico - Mainside have drinking water violations?
Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in January 2026. The violations listed here began between January 2019 and January 2026. By type: 7 monitoring and reporting and 5 contaminant level above the legal limit. The contaminant or rule involved most often is Total trihalomethanes (TTHM) (5 of them). EPA lists 8 as resolved and 4 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 |
|---|---|---|---|---|
| 2026-01-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Archived |
| 2025-10-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Archived |
| 2025-07-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Archived |
| 2025-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Archived |
| 2019-10-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Carbon, totalcode 2920 | No | Resolved |
| 2019-04-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02 | Total trihalomethanes (TTHM)code 2950 | Yes | Resolved |
| 2019-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Bariumcode 1010 | No | Resolved |
| 2019-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Antimonycode 1074 | No | Resolved |
| 2019-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Cadmiumcode 1015 | No | Resolved |
| 2019-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Thalliumcode 1085 | No | Resolved |
| 2019-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Chromiumcode 1020 | No | Resolved |
| 2019-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nickelcode 1036 | 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.
Mcb Quantico - Mainside: frequently asked questions
Who runs Mcb Quantico - Mainside?
Mcb Quantico - Mainside (PWSID VA6153675) is a community water system owned by the federal government. It is regulated by the VA state drinking water program.
How many people does Mcb Quantico - Mainside serve?
Mcb Quantico - Mainside reports serving 19,000 people through 1,314 service connections in Prince William County, Virginia.
Where does Mcb Quantico - Mainside 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 Mcb Quantico - Mainside have any drinking water violations?
Of the 12 most recent violations in EPA's records, 5 are 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 Mcb Quantico - Mainside'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, 5 are 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 VA state drinking water program.
Where can I find Mcb Quantico - Mainside's water quality report?
As a community water system, Mcb Quantico - Mainside 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 Prince William County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Pwcsa - East | Prince William | 168,747 | Community | Purchased surface water |
| Pwcsa - West | Prince William | 136,409 | Community | Purchased surface water |
| Dale City | Prince William | 72,062 | Community | Purchased surface water |
| Quantico Mcb-Camp Barrett | Prince William | 8,689 | Community | Purchased surface water |
| Bull Run Mountain/Evergreen (Brme) | Prince William | 1,803 | Community | Groundwater |
| Brentsville High School | Prince William | 1,600 | Non-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, “Mcb Quantico - Mainside, PWSID VA6153675, Virginia”, https://aquacensus.com/water-systems/virginia/mcb-quantico-mainside-va6153675 (data as of October 1, 2026).