Does Big Sky, MT tap water have any EPA-reported violations?

As of June 2026, EPA SDWIS records show 154 violation(s) across the community water systems serving Big Sky, of which 2 are classified by the EPA as health-based. Most older violations have returned to compliance; see the per-system list.

Where does Big Sky, MT tap water come from?

Big Sky is served by 12 active community water system(s). Their primary sources, per EPA records, are: groundwater.

MT / Big Sky

MT · Tap water records

Big Sky tap water, in plain English

Here is what the EPA's own data shows about tap water in Big Sky. According to EPA SDWIS data retrieved June 2026, Big Sky is served by 12 active community water systems, together reported to serve about 5,574 people.

As of June 2026, EPA records show 154 violations across the community water system(s) serving Big Sky, going back to the earliest EPA record. 2 of these are classified by the EPA as health-based (a contaminant recorded above the limit the EPA tracks); the rest are monitoring or reporting violations. Each is listed by system below, with its status.

12

Community water systems
~5,574

People served (EPA-reported)
June 2026

EPA records reviewed through

What the EPA has on record, by system

Big Sky County Water And Sewer Dist 363

4,132 served · groundwater · PWSID MT0002385

Monitoring Nitrate-Nitrite: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2025. 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 2014 and July 2020. 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 2020. 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 January 1994 and January 2014. 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. EPA records do not show all of these as returned to compliance.
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 2 times in January 2008. EPA records do not show all of these as returned to compliance.

Andesite Ridge Water System

450 served · groundwater · PWSID MT0004468

Health-based Lead and Copper Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in July 2012. 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 once in July 2020. All have since returned to compliance, per EPA records.
Monitoring Groundwater Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in November 2010. 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 2009. All have since returned to compliance, per EPA records.

Lower Pioneer Mountain Water System

350 served · groundwater · PWSID MT0004462

Health-based Revised Total Coliform Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in September 2020. 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 once in July 2020. 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 2010. 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 January 2008 and October 2009. All have since returned to compliance, per EPA records.

Lazy J South Subdivision

122 served · groundwater · PWSID MT0004432

Monitoring Revised Total Coliform Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in September 2019. All have since returned to compliance, per EPA records.

Encampment Trail

100 served · groundwater · PWSID MT0004916

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 2020. 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 3 times between July 2016 and January 2017. 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 3 times between July 2016 and January 2017. All have since returned to compliance, per EPA records.
Monitoring OXAMYL: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Simazine: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Di(2-ethylhexyl) phthalate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Picloram: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Dinoseb: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Hexachlorocyclopentadiene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Aldicarb sulfoxide: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Aldicarb sulfone: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Metolachlor: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Carbofuran: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Endrin: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Aldicarb: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Atrazine: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring LASSO: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Heptachlor: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring 3-Hydroxycarbofuran: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Heptachlor epoxide: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Dieldrin: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Butachlor: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Propachlor: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring 2,4-D: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring BHC-GAMMA: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring 2,4,5-TP: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring HEXACHLOROBENZENE: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Benzo(a)pyrene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Pentachlorophenol: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Aldrin: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Dicamba: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Metribuzin: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Chlordane: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Methoxychlor: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Toxaphene: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Carbaryl: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Methomyl: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Dalapon: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.
Monitoring Di(2-ethylhexyl) adipate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times in July 2016. All have since returned to compliance, per EPA records.