Public water system · CT0520011
ActiveCtwc - Unionville System
At a glance
Ctwc - Unionville System (PWSID CT0520011) is an active community water system in Hartford County, Connecticut. It reports serving 14,693 people through 6,319 service connections. Its primary water source is purchased surface water, and EPA lists it as privately owned. EPA's records list 6 violations for this system; 3 are health-based, and the most recent began in May 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
14,693
Service connections
6,319
Primary source
SWP
Purchased surface water
System type
CWS
Community water system
System record
How does Ctwc - Unionville System compare with other water systems in Hartford County?
By EPA's size categories, Ctwc - Unionville System is a large system (10,001 to 100,000 people). Hartford County has 219 active public water systems. Its population served is about 3.8 times the county average of 3,818 people per system, and accounts for 1.8% of the 836,032 people reported by systems filed under the county. Across Connecticut, the 2,363 active systems average 1,247 people each. Nationally, the average active community water system reports serving 6,703 people, so Ctwc - Unionville System is about twice 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. Connecticut has 481 active community water systems, 20% of the state's 2,363 active systems. Purchased surface water means the system buys surface water from another public water system rather than drawing its own. 52 Connecticut systems (2.2%) list purchased surface water as their primary source.
Who owns and regulates Ctwc - Unionville System?
EPA lists Ctwc - Unionville System as privately owned. The CT state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 179 of the 219 active systems in Hartford County (82%) are also privately owned.
Does Ctwc - Unionville System have drinking water violations?
EPA's records list 6 violations for this system; 3 are health-based, and the most recent began in May 2026. The violations listed here began between April 1991 and May 2026. By type: 3 monitoring and reporting, 2 required treatment not met and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Total coliform bacteria (TCR) (3 of them). EPA lists 5 as resolved and 1 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 |
|---|---|---|---|---|
| 2026-05-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Groundwater Rulecode 0700 | Yes | Archived |
| 2019-11-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Groundwater Rulecode 0700 | Yes | Resolved |
| 2016-12-30 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2002-08-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1999-01-01 | Monitoring and reportingMonitoring, Repeat Major (TCR) · code 25 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1991-04-01 | Monitoring and reportingMonitoring, Repeat Minor (TCR) · code 26 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
All 6 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.
Ctwc - Unionville System: frequently asked questions
Who runs Ctwc - Unionville System?
Ctwc - Unionville System (PWSID CT0520011) is a community water system privately owned. It is regulated by the CT state drinking water program.
How many people does Ctwc - Unionville System serve?
Ctwc - Unionville System reports serving 14,693 people through 6,319 service connections in Hartford County, Connecticut.
Where does Ctwc - Unionville System get its water?
EPA SDWIS lists this system's primary water source as purchased surface water. Purchased surface water means the system buys surface water from another public water system rather than drawing its own.
Does Ctwc - Unionville System have any drinking water violations?
EPA's records list 6 violations for this system; 3 are health-based, and the most recent began in May 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 Ctwc - Unionville System'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 6 violations for this system; 3 are health-based, and the most recent began in May 2026. For current results, consult the system's annual water quality report, EPA ECHO, or the CT state drinking water program.
Where can I find Ctwc - Unionville System's water quality report?
As a community water system, Ctwc - Unionville System 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 Hartford County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Metropolitan District Commission | Hartford | 390,887 | Community | Surface water |
| Ctwc - Northern Reg-Western System | Hartford | 101,313 | Community | Surface water |
| New Britain Water Department | Hartford | 73,534 | Community | Surface water |
| Bristol Water Department | Hartford | 52,079 | Community | Surface water |
| Manchester Water Department | Hartford | 51,198 | Community | Surface water |
| Southington Water Department | Hartford | 43,069 | 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, “Ctwc - Unionville System, PWSID CT0520011, Connecticut”, https://aquacensus.com/water-systems/connecticut/ctwc-unionville-system-ct0520011 (data as of October 1, 2026).