DENTON, MT · Fergus County

DENTON TOWN OF Water System

Current status

1 open health-based violation on record as of July 4, 2026. See the violation history below for contaminant and status details.

This system's next federally required Consumer Confidence Report is due July 1, 2027, under the EPA's revised reporting rule.

Data sourced from the EPA ECHO database (SDWA bulk download), last refreshed July 4, 2026. This is a record-keeping and public-information tool — it does not replace Montana’s official records. Always confirm current status with Montana before making decisions based on this information.

System facts

System ID (PWSID): MT0000199
System type: Community Water System
Population served: 255
Service connections: 169
Ownership: local government
Water source: surface water (rivers, lakes, or reservoirs)

Violation history

Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
February 1, 2026 – February 28, 2026
Archived
Monitoring of Treatment (SWTR-Filter)
—
Surface Water Treatment Rule
February 1, 2026 – February 28, 2026
Archived
Monitoring of Treatment (SWTR-Filter)
—
Surface Water Treatment Rule
January 1, 2026 – January 31, 2026
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
January 1, 2026 – January 31, 2026
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
December 1, 2025 – December 31, 2025
Archived
Monitoring of Treatment (SWTR-Filter)
—
Surface Water Treatment Rule
December 1, 2025 – December 31, 2025
Archived
Monitoring of Treatment (SWTR-Filter)
—
Surface Water Treatment Rule
November 1, 2025 – November 30, 2025
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
November 1, 2025 – November 30, 2025
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
October 1, 2025 – October 31, 2025
Archived
Monitoring of Treatment (SWTR-Filter)
—
Surface Water Treatment Rule
October 1, 2025 – October 31, 2025
Archived
Monitoring of Treatment (SWTR-Filter)
—
Surface Water Treatment Rule
September 1, 2025 – September 30, 2025
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
September 1, 2025 – September 30, 2025
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
August 1, 2025 – August 31, 2025
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
July 1, 2025 – July 31, 2025
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
June 1, 2025 – June 30, 2025
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
May 1, 2025 – May 31, 2025
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
April 1, 2025 – April 30, 2025
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
March 1, 2025 – March 31, 2025
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
February 1, 2025 – February 28, 2025
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
January 1, 2025 – January 31, 2025
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
December 1, 2024 – December 31, 2024
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
November 1, 2024 – November 30, 2024
Archived
Treatment Technique (SWTR and GWR)
Health-based
Surface Water Treatment Rule
October 1, 2024 – October 31, 2024
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
September 1, 2024 – September 30, 2024
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
August 1, 2024 – August 31, 2024
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
July 1, 2024 – July 31, 2024
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
June 1, 2024 – June 30, 2024
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
May 1, 2024 – May 31, 2024
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
April 1, 2024 – April 30, 2024
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
March 1, 2024 – March 31, 2024
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
February 1, 2024 – February 29, 2024
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
January 1, 2024 – January 31, 2024
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
December 1, 2023 – December 31, 2023
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
November 1, 2023 – November 30, 2023
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
October 1, 2023 – October 31, 2023
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
September 1, 2023 – September 30, 2023
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
August 1, 2023 – August 31, 2023
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
July 1, 2023 – July 31, 2023
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
June 1, 2023 – June 30, 2023
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
May 1, 2023 – May 31, 2023
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
April 1, 2023 – April 30, 2023
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
March 1, 2023 – March 31, 2023
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
February 1, 2023 – February 28, 2023
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
January 1, 2023 – January 31, 2023
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
December 1, 2022 – December 31, 2022
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
November 1, 2022 – November 30, 2022
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
October 1, 2022 – October 31, 2022
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
September 1, 2022 – September 30, 2022
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
August 1, 2022 – August 31, 2022
Archived
Consumer Confidence Report Complete Failure to Report
—
Consumer Confidence Rule
July 1, 2022 – August 12, 2022
Resolved
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
July 1, 2022 – July 31, 2022
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
June 1, 2022 – June 30, 2022
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
May 1, 2022 – May 31, 2022
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
April 1, 2022 – April 30, 2022
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
March 1, 2022 – March 31, 2022
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
February 1, 2022 – February 28, 2022
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
January 1, 2022 – January 31, 2022
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
December 1, 2021 – December 31, 2021
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
November 1, 2021 – November 30, 2021
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
October 1, 2021 – October 31, 2021
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
September 1, 2021 – September 30, 2021
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
August 1, 2021 – August 31, 2021
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
July 1, 2021 – July 31, 2021
Archived
Consumer Confidence Report Complete Failure to Report
—
Consumer Confidence Rule
July 1, 2021 – July 27, 2021
Resolved
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
June 1, 2021 – June 30, 2021
Archived
Monitoring, Routine (RTCR)
—
Revised Total Coliform Rule
June 1, 2021 – June 30, 2021
Resolved
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
May 1, 2021 – May 31, 2021
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
April 1, 2021 – April 30, 2021
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
March 1, 2021 – March 31, 2021
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
February 1, 2021 – February 28, 2021
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
January 1, 2021 – January 31, 2021
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
December 1, 2020 – December 31, 2020
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
November 1, 2020 – November 30, 2020
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
October 1, 2020 – October 31, 2020
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
September 1, 2020 – September 30, 2020
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
August 1, 2020 – August 31, 2020
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
July 1, 2020 – July 31, 2020
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
June 1, 2020 – June 30, 2020
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
May 1, 2020 – May 31, 2020
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
April 1, 2020 – April 30, 2020
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
March 1, 2020 – March 31, 2020
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
February 1, 2020 – February 29, 2020
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
January 1, 2020 – January 31, 2020
Archived
Treatment Technique (SWTR and GWR)
Health-based
Long Term 2 Enhanced Surface Water Treatment Rule
December 1, 2019 – December 31, 2019
Archived
Monitoring, Regular
—
Nitrate-Nitrite
October 1, 2018 – December 31, 2018
Resolved
Monitoring, Routine (RTCR)
—
Revised Total Coliform Rule
June 1, 2017 – June 30, 2017
Resolved
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate-Nitrite
January 1, 2016 – March 31, 2016
Resolved
Failure to Filter (SWTR)
Health-based
Surface Water Treatment Rule
June 3, 2014
Addressed
Lead Consumer Notice
—
Lead and Copper Rule
January 1, 2014 – January 30, 2014
Resolved
Consumer Confidence Report Inadequate Reporting
—
Consumer Confidence Rule
October 1, 2013 – January 2, 2014
Resolved
Consumer Confidence Report Complete Failure to Report
—
Consumer Confidence Rule
July 1, 2013 – August 16, 2013
Resolved
Consumer Confidence Report Complete Failure to Report
—
Consumer Confidence Rule
July 1, 2012 – July 2, 2012
Resolved
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate-Nitrite
July 1, 2012 – September 30, 2012
Resolved
Failure To Address Deficiency
Health-based
Groundwater Rule
November 21, 2011 – June 20, 2015
Resolved
Consumer Confidence Report Inadequate Reporting
—
Consumer Confidence Rule
October 1, 2011 – November 9, 2011
Resolved
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate-Nitrite
April 1, 2007 – June 30, 2007
Resolved
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate-Nitrite
October 1, 2006 – December 31, 2006
Resolved
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate-Nitrite
January 1, 2006 – December 31, 2006
Resolved
Monitoring, Regular
—
Nitrate-Nitrite
January 1, 2005 – December 31, 2005
Resolved
Monitoring, Regular
—
Chromium
January 1, 1999 – December 31, 2001
Resolved
Monitoring, Regular
—
Cadmium
January 1, 1999 – December 31, 2001
Resolved
Monitoring, Regular
—
Selenium
January 1, 1999 – December 31, 2001
Resolved
Monitoring, Regular
—
Mercury
January 1, 1999 – December 31, 2001
Resolved
Monitoring, Regular
—
Fluoride
January 1, 1999 – December 31, 2001
Resolved
Maximum Contaminant Level Violation, Average
Health-based
Nitrate
April 16, 1987 – April 15, 1990
Resolved
Maximum Contaminant Level Violation, Average
Health-based
Nitrate
October 1, 1980 – October 31, 1980
Archived

Archived closed in EPA's records (typically due to age or a data correction)Resolved addressed and confirmed by the stateAddressed corrective action reported, pending final confirmation

Period	Violation	Contaminant / rule	Health-based	Status
February 1, 2026 – February 28, 2026	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
February 1, 2026 – February 28, 2026	Monitoring of Treatment (SWTR-Filter)	Surface Water Treatment Rule	—	Archived
January 1, 2026 – January 31, 2026	Monitoring of Treatment (SWTR-Filter)	Surface Water Treatment Rule	—	Archived
January 1, 2026 – January 31, 2026	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
December 1, 2025 – December 31, 2025	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
December 1, 2025 – December 31, 2025	Monitoring of Treatment (SWTR-Filter)	Surface Water Treatment Rule	—	Archived
November 1, 2025 – November 30, 2025	Monitoring of Treatment (SWTR-Filter)	Surface Water Treatment Rule	—	Archived
November 1, 2025 – November 30, 2025	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
October 1, 2025 – October 31, 2025	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
October 1, 2025 – October 31, 2025	Monitoring of Treatment (SWTR-Filter)	Surface Water Treatment Rule	—	Archived
September 1, 2025 – September 30, 2025	Monitoring of Treatment (SWTR-Filter)	Surface Water Treatment Rule	—	Archived
September 1, 2025 – September 30, 2025	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
August 1, 2025 – August 31, 2025	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
July 1, 2025 – July 31, 2025	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
June 1, 2025 – June 30, 2025	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
May 1, 2025 – May 31, 2025	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
April 1, 2025 – April 30, 2025	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
March 1, 2025 – March 31, 2025	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
February 1, 2025 – February 28, 2025	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
January 1, 2025 – January 31, 2025	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
December 1, 2024 – December 31, 2024	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
November 1, 2024 – November 30, 2024	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
October 1, 2024 – October 31, 2024	Treatment Technique (SWTR and GWR)	Surface Water Treatment Rule	Health-based	Archived
September 1, 2024 – September 30, 2024	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
August 1, 2024 – August 31, 2024	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
July 1, 2024 – July 31, 2024	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
June 1, 2024 – June 30, 2024	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
May 1, 2024 – May 31, 2024	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
April 1, 2024 – April 30, 2024	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
March 1, 2024 – March 31, 2024	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
February 1, 2024 – February 29, 2024	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
January 1, 2024 – January 31, 2024	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
December 1, 2023 – December 31, 2023	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
November 1, 2023 – November 30, 2023	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
October 1, 2023 – October 31, 2023	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
September 1, 2023 – September 30, 2023	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
August 1, 2023 – August 31, 2023	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
July 1, 2023 – July 31, 2023	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
June 1, 2023 – June 30, 2023	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
May 1, 2023 – May 31, 2023	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
April 1, 2023 – April 30, 2023	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
March 1, 2023 – March 31, 2023	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
February 1, 2023 – February 28, 2023	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
January 1, 2023 – January 31, 2023	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
December 1, 2022 – December 31, 2022	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
November 1, 2022 – November 30, 2022	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
October 1, 2022 – October 31, 2022	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
September 1, 2022 – September 30, 2022	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
August 1, 2022 – August 31, 2022	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
July 1, 2022 – August 12, 2022	Consumer Confidence Report Complete Failure to Report	Consumer Confidence Rule	—	Resolved
July 1, 2022 – July 31, 2022	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
June 1, 2022 – June 30, 2022	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
May 1, 2022 – May 31, 2022	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
April 1, 2022 – April 30, 2022	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
March 1, 2022 – March 31, 2022	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
February 1, 2022 – February 28, 2022	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
January 1, 2022 – January 31, 2022	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
December 1, 2021 – December 31, 2021	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
November 1, 2021 – November 30, 2021	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
October 1, 2021 – October 31, 2021	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
September 1, 2021 – September 30, 2021	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
August 1, 2021 – August 31, 2021	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
July 1, 2021 – July 31, 2021	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
July 1, 2021 – July 27, 2021	Consumer Confidence Report Complete Failure to Report	Consumer Confidence Rule	—	Resolved
June 1, 2021 – June 30, 2021	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
June 1, 2021 – June 30, 2021	Monitoring, Routine (RTCR)	Revised Total Coliform Rule	—	Resolved
May 1, 2021 – May 31, 2021	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
April 1, 2021 – April 30, 2021	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
March 1, 2021 – March 31, 2021	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
February 1, 2021 – February 28, 2021	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
January 1, 2021 – January 31, 2021	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
December 1, 2020 – December 31, 2020	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
November 1, 2020 – November 30, 2020	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
October 1, 2020 – October 31, 2020	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
September 1, 2020 – September 30, 2020	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
August 1, 2020 – August 31, 2020	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
July 1, 2020 – July 31, 2020	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
June 1, 2020 – June 30, 2020	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
May 1, 2020 – May 31, 2020	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
April 1, 2020 – April 30, 2020	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
March 1, 2020 – March 31, 2020	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
February 1, 2020 – February 29, 2020	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
January 1, 2020 – January 31, 2020	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
December 1, 2019 – December 31, 2019	Treatment Technique (SWTR and GWR)	Long Term 2 Enhanced Surface Water Treatment Rule	Health-based	Archived
October 1, 2018 – December 31, 2018	Monitoring, Regular	Nitrate-Nitrite	—	Resolved
June 1, 2017 – June 30, 2017	Monitoring, Routine (RTCR)	Revised Total Coliform Rule	—	Resolved
January 1, 2016 – March 31, 2016	Maximum Contaminant Level Violation, Single Sample	Nitrate-Nitrite	Health-based	Resolved
June 3, 2014	Failure to Filter (SWTR)	Surface Water Treatment Rule	Health-based	Addressed
January 1, 2014 – January 30, 2014	Lead Consumer Notice	Lead and Copper Rule	—	Resolved
October 1, 2013 – January 2, 2014	Consumer Confidence Report Inadequate Reporting	Consumer Confidence Rule	—	Resolved
July 1, 2013 – August 16, 2013	Consumer Confidence Report Complete Failure to Report	Consumer Confidence Rule	—	Resolved
July 1, 2012 – July 2, 2012	Consumer Confidence Report Complete Failure to Report	Consumer Confidence Rule	—	Resolved
July 1, 2012 – September 30, 2012	Maximum Contaminant Level Violation, Single Sample	Nitrate-Nitrite	Health-based	Resolved
November 21, 2011 – June 20, 2015	Failure To Address Deficiency	Groundwater Rule	Health-based	Resolved
October 1, 2011 – November 9, 2011	Consumer Confidence Report Inadequate Reporting	Consumer Confidence Rule	—	Resolved
April 1, 2007 – June 30, 2007	Maximum Contaminant Level Violation, Single Sample	Nitrate-Nitrite	Health-based	Resolved
October 1, 2006 – December 31, 2006	Maximum Contaminant Level Violation, Single Sample	Nitrate-Nitrite	Health-based	Resolved
January 1, 2006 – December 31, 2006	Maximum Contaminant Level Violation, Single Sample	Nitrate-Nitrite	Health-based	Resolved
January 1, 2005 – December 31, 2005	Monitoring, Regular	Nitrate-Nitrite	—	Resolved
January 1, 1999 – December 31, 2001	Monitoring, Regular	Chromium	—	Resolved
January 1, 1999 – December 31, 2001	Monitoring, Regular	Cadmium	—	Resolved
January 1, 1999 – December 31, 2001	Monitoring, Regular	Selenium	—	Resolved
January 1, 1999 – December 31, 2001	Monitoring, Regular	Mercury	—	Resolved
January 1, 1999 – December 31, 2001	Monitoring, Regular	Fluoride	—	Resolved
April 16, 1987 – April 15, 1990	Maximum Contaminant Level Violation, Average	Nitrate	Health-based	Resolved
October 1, 1980 – October 31, 1980	Maximum Contaminant Level Violation, Average	Nitrate	Health-based	Archived

Archived closed in EPA's records (typically due to age or a data correction)Resolved addressed and confirmed by the stateAddressed corrective action reported, pending final confirmation

Enforcement actions

February 2, 2026State Public Notification requested223 linked violations
March 31, 2025State Public Notification requested40 linked violations
September 13, 2023State Public Notification requested33 linked violations
September 13, 2023State Public Notification requested63 linked violations
June 17, 2014State Other159 linked violations
January 28, 2009Federal Compliance achieved88 linked violations
July 5, 2007Federal Final Administrative Order issued11 linked violations
June 5, 2007Federal issued Formal Notice of Violation3 linked violations

Contact

TOWN OF DENTON

406-567-2571

DENTON, MT 59430