Libby tap water, in plain English

• Health-based Interim Enhanced Surface Water Treatment Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 9 times between December 2015 and December 2025. The EPA record for these does not include a measured level. EPA records do not show all of these as returned to compliance.
• Health-based Long Term 2 Enhanced Surface Water Treatment Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 3 times in March 2022. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
• Health-based Surface Water Treatment Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in January 1993. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
• Monitoring 1,2,4-Trichlorobenzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring cis-1,2-Dichloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring Xylenes, Total: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring DICHLOROMETHANE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring o-Dichlorobenzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring p-Dichlorobenzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring Vinyl chloride: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring 1,1-Dichloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring trans-1,2-Dichloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring 1,2-Dichloroethane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring 1,1,1-Trichloroethane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring Carbon tetrachloride: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring 1,2-Dichloropropane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring Trichloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring 1,1,2-Trichloroethane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring Tetrachloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring CHLOROBENZENE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring Benzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring Toluene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring Ethylbenzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring Styrene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2021. All have since returned to compliance, per EPA records.
• Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times between February 2007 and July 2019. All have since returned to compliance, per EPA records.
• Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times between October 2001 and January 2011. All have since returned to compliance, per EPA records.

• Health-based Revised Total Coliform Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in September 2017. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
• Health-based Groundwater Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in June 2013. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
• Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times between July 2019 and July 2023. All have since returned to compliance, per EPA records.
• Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times between July 1993 and January 2011. All have since returned to compliance, per EPA records.
• Monitoring Asbestos: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2011. All have since returned to compliance, per EPA records.

• Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in December 2024. All have since returned to compliance, per EPA records.
• Monitoring TTHM: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Total Haloacetic Acids (HAA5): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in July 2018. All have since returned to compliance, per EPA records.
• Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2014. All have since returned to compliance, per EPA records.

• Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 7 times between July 2024 and October 2025. All have since returned to compliance, per EPA records.
• Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times between July 2003 and July 2005. All have since returned to compliance, per EPA records.

• Health-based Revised Total Coliform Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in August 2019. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
• Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 6 times between July 2010 and July 2019. All have since returned to compliance, per EPA records.
• Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 5 times between July 1993 and October 2016. All have since returned to compliance, per EPA records.

• Health-based Revised Total Coliform Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 2 times between August 2016 and January 2017. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
• Health-based Coliform (TCR): a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 2 times between November 2015 and December 2015. The EPA record for these does not include a measured level. All have since returned to compliance, per EPA records.
• Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 9 times between July 1993 and January 2026. All have since returned to compliance, per EPA records.
• Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 26 times between July 2011 and October 2025. All have since returned to compliance, per EPA records.
• Monitoring Nitrate-Nitrite: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times between January 2014 and January 2022. EPA records do not show all of these as returned to compliance.
• Monitoring Nickel: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Antimony, Total: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Beryllium, Total: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Thallium, Total: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring 1,2,4-Trichlorobenzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring cis-1,2-Dichloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Xylenes, Total: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring DICHLOROMETHANE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring o-Dichlorobenzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring p-Dichlorobenzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Vinyl chloride: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring 1,1-Dichloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring trans-1,2-Dichloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring 1,2-Dichloroethane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring 1,1,1-Trichloroethane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Carbon tetrachloride: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring 1,2-Dichloropropane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Trichloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring 1,1,2-Trichloroethane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Tetrachloroethylene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring CHLOROBENZENE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Benzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Toluene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Ethylbenzene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Styrene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Endrin: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring BHC-GAMMA: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Methoxychlor: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Toxaphene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Dalapon: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Di(2-ethylhexyl) adipate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring OXAMYL: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Simazine: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Di(2-ethylhexyl) phthalate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Picloram: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Dinoseb: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Hexachlorocyclopentadiene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Carbofuran: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Atrazine: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring LASSO: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Heptachlor: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Heptachlor epoxide: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring 2,4-D: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring 2,4,5-TP: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring HEXACHLOROBENZENE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Benzo(a)pyrene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Pentachlorophenol: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Chlordane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring CYANIDE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Diquat: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Endothall: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Glyphosate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Total Polychlorinated Biphenyls (PCB): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring 1,2-DIBROMO-3-CHLOROPROPANE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring ETHYLENE DIBROMIDE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring Asbestos: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2020. EPA records do not show all of these as returned to compliance.
• Monitoring E. COLI: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 5 times between August 2015 and March 2017. EPA records do not show all of these as returned to compliance.
• Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times between April 2016 and March 2017. All have since returned to compliance, per EPA records.
• Monitoring Gross Alpha, Excl. Radon and U: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2008. All have since returned to compliance, per EPA records.
• Monitoring Combined Radium (-226 and -228): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2008. All have since returned to compliance, per EPA records.

• Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 12 times between July 2019 and October 2025. All have since returned to compliance, per EPA records.
• Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in February 2025. EPA records do not show all of these as returned to compliance.
• Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 7 times between January 1997 and July 2024. All have since returned to compliance, per EPA records.
• Monitoring Manganese: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2024. EPA records do not show all of these as returned to compliance.
• Monitoring Nitrate-Nitrite: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 3 times in January 2024. EPA records do not show all of these as returned to compliance.

• Monitoring Nitrate-Nitrite: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in January 2024. All have since returned to compliance, per EPA records.
• Monitoring E. COLI: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in December 2019. All have since returned to compliance, per EPA records.
• Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times between April 2016 and June 2019. All have since returned to compliance, per EPA records.
• Monitoring Consumer Confidence Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times between July 2006 and July 2008. All have since returned to compliance, per EPA records.
• Monitoring Gross Alpha, Excl. Radon and U: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2008. All have since returned to compliance, per EPA records.
• Monitoring Combined Radium (-226 and -228): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2008. All have since returned to compliance, per EPA records.
• Monitoring Lead and Copper Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in October 2004. All have since returned to compliance, per EPA records.

As of June 2026, EPA records show no reported violations for this system in the period covered. This is not a guarantee about every substance, or about the water inside your home's plumbing.