Community Water System · PWS CT1180021
Aquarion-Ridgefield Knolls
Shelton, Connecticut 06484 - drinking water served from groundwater sources to 958 people, tracked in EPA SDWIS and UCMR5.
- 958
- People served
- 228
- EPA violations
- 55
- Health-based
- Untested
- UCMR5 result
The verdict
EPA records 228 drinking-water violations at Aquarion-Ridgefield Knolls, 24% of them health-based - above the Connecticut per-system average.
- 228
- Total EPA violations on record
- 24%
- Health-based (MCL / treatment failure)
- 958
- People served by this system
- N/A
- PFAS compounds detected (UCMR5)
Water Quality Snapshot: Aquarion-Ridgefield Knolls
Aquarion-Ridgefield Knolls is a private-owned community water system that delivers drinking water to 958 residents in Shelton, Connecticut (Fairfield County) through 223 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 228 total violations for this system , of which 55 (24%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 157 monitoring and reporting violations are on file. The most recent violation on record dates to 2021.
The most frequently cited contaminant at this system is Coliform (TCR), recorded in 46 violations (MCL, health-based). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.
Across Connecticut, EPA tracks 2,332 public water systems serving 2,886,005 people, with 206,662 cumulative violations and 21,779 health-based violations on record. About 94% of systems in the state carry at least one violation, and state-wide the average per system is 88.6 violations. Statewide, 40 of 63 UCMR5-tested systems have reported PFAS detections (63.5%).
Aquarion-Ridgefield Knolls's 228 violations sit above the Connecticut average.
All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.
System Details
- System Type
- Community
- Owner Type
- Private
- Connections
- 223
- County
- Fairfield
- School/Daycare
- No
- MCL Violations
- 46
- Monitoring Violations
- 157
- Treatment Tech Violations
- 9
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MCL | 46 | 2003 |
| Coliform (TCR) | MR | 15 | 2006 |
| Lead and Copper Rule | MR | 10 | 2021 |
| Lead and Copper Rule | TT | 9 | 2008 |
| Consumer Confidence Rule | Other | 6 | 2018 |
| 1,1,2-Trichloroethane | MR | 4 | 1993 |
| Trichloroethylene | MR | 4 | 1993 |
| 1,2-Dichloropropane | MR | 4 | 1993 |
| 1,2-Dichloroethane | MR | 4 | 1993 |
| trans-1,2-Dichloroethylene | MR | 4 | 1993 |
| 1,1-Dichloroethylene | MR | 4 | 1993 |
| Vinyl chloride | MR | 4 | 1993 |
| p-Dichlorobenzene | MR | 4 | 1993 |
| DICHLOROMETHANE | MR | 4 | 1993 |
| ETHYLENE DIBROMIDE | MR | 4 | 1993 |
| Beryllium, Total | MR | 4 | 1991 |
| Antimony, Total | MR | 4 | 1991 |
| Selenium | MR | 4 | 1991 |
| Nickel | MR | 4 | 1991 |
| Mercury | MR | 4 | 1991 |
| Coliform (TCR) | Other | 4 | 1995 |
| CYANIDE | MR | 4 | 1991 |
| Chromium | MR | 4 | 1991 |
| Cadmium | MR | 4 | 1991 |
| Barium | MR | 4 | 1991 |
| Benzene | MR | 4 | 1993 |
| Toluene | MR | 4 | 1993 |
| o-Dichlorobenzene | MR | 4 | 1993 |
| 1,1,1-Trichloroethane | MR | 4 | 1993 |
| CHLOROBENZENE | MR | 4 | 1993 |
Verify This Water System
The figures above are aggregated from EPA's public databases. To verify the underlying records, or to file a complaint, request a Consumer Confidence Report, or check current monitoring status, go directly to the federal and state regulators that enforce the Safe Drinking Water Act for Aquarion-Ridgefield Knolls.
EPA SDWIS, Federal Reports
EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:
View PWS ID CT1180021 on SDWISSource: EPA SDWIS Federal Reports Search
Connecticut Drinking Water Authority
Connecticut's primacy agency administers the Safe Drinking Water Act locally. Search EPA SDWIS for the current state contact, or use the state's public health or environment department portal.
Find CT regulator via EPA SDWISViolation Timeline
Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.
| Year (latest) | Contaminant | Category | Count | EPA Record |
|---|---|---|---|---|
| 2021 | Lead and Copper Rule | MR | 10 | SDWIS / CT1180021 / 5000 |
| 2018 | Consumer Confidence Rule | Other | 6 | SDWIS / CT1180021 / 7000 |
| 2008 | Lead and Copper Rule | TT | 9 | SDWIS / CT1180021 / 5000 |
| 2006 | Coliform (TCR) | MR | 15 | SDWIS / CT1180021 / 3100 |
| 2003 | Coliform (TCR) | MCL | 46 | SDWIS / CT1180021 / 3100 |
| 1995 | Coliform (TCR) | Other | 4 | SDWIS / CT1180021 / 3100 |
| 1993 | 1,1,2-Trichloroethane | MR | 4 | SDWIS / CT1180021 / 2985 |
| 1993 | Trichloroethylene | MR | 4 | SDWIS / CT1180021 / 2984 |
| 1993 | 1,2-Dichloropropane | MR | 4 | SDWIS / CT1180021 / 2983 |
| 1993 | 1,2-Dichloroethane | MR | 4 | SDWIS / CT1180021 / 2980 |
| 1993 | trans-1,2-Dichloroethylene | MR | 4 | SDWIS / CT1180021 / 2979 |
| 1993 | 1,1-Dichloroethylene | MR | 4 | SDWIS / CT1180021 / 2977 |
| 1993 | Vinyl chloride | MR | 4 | SDWIS / CT1180021 / 2976 |
| 1993 | p-Dichlorobenzene | MR | 4 | SDWIS / CT1180021 / 2969 |
| 1993 | DICHLOROMETHANE | MR | 4 | SDWIS / CT1180021 / 2964 |
How Aquarion-Ridgefield Knolls Compares
Cross-reference this system's record against state averages and the federal MCL framework for context.
| Metric | Aquarion-Ridgefield Knolls | Connecticut avg | Federal benchmark |
|---|---|---|---|
| Total violations | 228 | 88.6 | SDWA compliance, any non-zero count is a recorded breach |
| Health-based violations | 55 | 9.3 | Indicates a contaminant exceeded a federal MCL |
| PFAS detection | None | 63.5% | EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt |
| Population served | 958 | 1,238 | Sizing context for compliance burden |
Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 2,332 regulated public water systems in Connecticut.
Federal MCL reference, Safe Drinking Water Act thresholds ▼
| Contaminant | Federal MCL / Action Level | Note |
|---|---|---|
| Lead | 0 mg/L (Action Level: 0.015 mg/L) | Lead and Copper Rule treatment technique |
| Arsenic | 0.010 mg/L (10 ppb) | Health-based MCL since 2006 |
| Total Coliform | Treatment technique (RTCR) | Indicator organism, monitoring trigger |
| PFOA / PFOS (PFAS) | 4.0 ppt each (final 2024 rule) | Compliance deadline 2029 (EPA proposed extending to 2031, not yet final as of May 2026) |
| Nitrate (as N) | 10 mg/L | Acute health risk for infants |
Frequently Asked Questions
Is Aquarion-Ridgefield Knolls water safe to drink? ▼
How many people does Aquarion-Ridgefield Knolls serve? ▼
What type of violations does Aquarion-Ridgefield Knolls have? ▼
Has PFAS been detected in Aquarion-Ridgefield Knolls water? ▼
What water source does Aquarion-Ridgefield Knolls use? ▼
Where does this data come from? ▼
Read our methodology - how this data is sourced, computed, and verified.
Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.