Public water system · CT1180021
ActiveAquarion-Ridgefield Knolls
At a glance
Aquarion-Ridgefield Knolls (PWSID CT1180021) is an active community water system in Fairfield County, Connecticut. It reports serving 958 people through 240 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in December 2021.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
958
Service connections
240
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Aquarion-Ridgefield Knolls compare with other water systems in Fairfield County?
By EPA's size categories, Aquarion-Ridgefield Knolls is a small system (501 to 3,300 people). Fairfield County has 337 active public water systems. Its population served is about 59% below the county average of 2,311 people per system, and accounts for 0.1% of the 778,730 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 Aquarion-Ridgefield Knolls 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. Connecticut has 481 active community water systems, 20% of the state's 2,363 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 2,263 Connecticut systems (96%) list groundwater as their primary source.
Who owns and regulates Aquarion-Ridgefield Knolls?
EPA lists Aquarion-Ridgefield Knolls 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. 286 of the 337 active systems in Fairfield County (85%) are also privately owned.
Does Aquarion-Ridgefield Knolls have drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in December 2021. The violations listed here began between November 2003 and December 2021. By type: 6 monitoring and reporting, 3 public notice, recordkeeping or other and 3 required treatment not met. The contaminant or rule involved most often is Lead and Copper Rule (7 of them). EPA lists 11 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 |
|---|---|---|---|---|
| 2021-12-30 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2018-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2015-12-30 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Unaddressed |
| 2008-07-01 | Required treatment not metOCCT/SOWT Study/Recommendation · code 57 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 2008-03-01 | Required treatment not metPublic Education · code 65 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 2007-01-01 | Monitoring and reportingWater Quality Parameter M/R · code 53 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2006-12-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2005-01-01 | Required treatment not metOCCT/SOWT Study/Recommendation · code 57 | Lead and Copper Rulecode 5000 | Yes | Resolved |
| 2004-08-10 | Public notice, recordkeeping or otherConsumer Confidence Report Inadequate Reporting · code 72 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2004-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2004-01-01 | Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2003-11-01 | Monitoring and reportingMonitoring, Repeat Major (TCR) · code 25 | Total coliform bacteria (TCR)code 3100 | 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.
Aquarion-Ridgefield Knolls: frequently asked questions
Who runs Aquarion-Ridgefield Knolls?
Aquarion-Ridgefield Knolls (PWSID CT1180021) is a community water system privately owned. It is regulated by the CT state drinking water program.
How many people does Aquarion-Ridgefield Knolls serve?
Aquarion-Ridgefield Knolls reports serving 958 people through 240 service connections in Fairfield County, Connecticut.
Where does Aquarion-Ridgefield Knolls 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 Aquarion-Ridgefield Knolls have any drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in December 2021. 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 Aquarion-Ridgefield Knolls' 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, 3 are health-based, and the most recent began in December 2021. For current results, consult the system's annual water quality report, EPA ECHO, or the CT state drinking water program.
Where can I find Aquarion-Ridgefield Knolls' water quality report?
As a community water system, Aquarion-Ridgefield Knolls 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 Fairfield County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Aquarion-Eastern Fairfield County | Fairfield | 351,756 | Community | Surface water |
| Aquarion-Stamford | Fairfield | 119,214 | Community | Surface water |
| Danbury Water Department | Fairfield | 62,055 | Community | Surface water |
| Aquarion-Greenwich | Fairfield | 53,297 | Community | Surface water |
| South Norwalk Electric & Water | Fairfield | 42,000 | Community | Surface water |
| Norwalk First Taxing District | Fairfield | 40,256 | 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, “Aquarion-Ridgefield Knolls, PWSID CT1180021, Connecticut”, https://aquacensus.com/water-systems/connecticut/aquarion-ridgefield-knolls-ct1180021 (data as of October 1, 2026).