Here is what the EPA's own data shows about tap water in Twin Falls. According to EPA SDWIS data retrieved October 2026, Twin Falls is served by 3 active community water systems, together reported to serve about 56,296 people.
As of October 2026, EPA records show 76 violations across the community water system(s) serving Twin Falls, going back to the earliest EPA record. 16 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.
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 February 2026. EPA records do not show all of these as returned to compliance.
Monitoring Chlorine: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in February 2026. EPA records do not show all of these as returned to compliance.
Monitoring Temperature (Centigrade): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2025. EPA records do not show all of these as returned to compliance.
Monitoring pH: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2025. EPA records do not show all of these as returned to compliance.
Monitoring Nitrate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 2 times between January 2022 and January 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 2 times in July 2022. 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 2 times between August 2010 and February 2015. All have since returned to compliance, per EPA records.
Monitoring Nitrite: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in January 2014. EPA records do not show all of these as returned to compliance.
Monitoring Public Notice: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 10 times between November 2010 and July 2012. All have since returned to compliance, per EPA records.
Meander Point Subd
140 served · groundwater · PWSID ID5420040
Health-based Arsenic: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 8 times between January 2019 and April 2022. The EPA record lists a level of 0.011 MG/L; the limit (MCL) is 0.01 MG/L. EPA records do not show all of these as returned to compliance.
Health-based Groundwater Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded 2 times in June 2020. 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 REVISIONS: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in October 2024. EPA records do not show all of these as returned to compliance.
Monitoring Groundwater Rule: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in June 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 once in October 2020. All have since returned to compliance, per EPA records.
Monitoring Chlorine: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 4 times between July 2014 and July 2015. All have since returned to compliance, per EPA records.
Riverside Trailer Court
35 served · groundwater · PWSID ID5160003
Health-based Groundwater 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 Revised Total Coliform Rule: a health-based violation (a contaminant recorded above the limit the EPA tracks), recorded once in May 2016. 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 4 times between August 2014 and March 2016. The EPA record for these does not include a measured level. 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 once in February 2026. EPA records do not show all of these as returned to compliance.
Monitoring Public Notice: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 13 times between May 2010 and November 2017. 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 8 times between March 2015 and June 2016. All have since returned to compliance, per EPA records.
Monitoring Nitrate: a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded once in April 2016. All have since returned to compliance, per EPA records.
Monitoring Coliform (TCR): a monitoring or reporting violation (a required test or report was late or missed — not a measured exceedance), recorded 9 times between April 2013 and January 2016. All have since returned to compliance, per EPA records.
What this means
A health-based violation means a contaminant was recorded above the limit the EPA tracks for it. A monitoring or reporting violation means a required test or report was late or missed — not that a contaminant was measured above a limit. “Returned to compliance” means the EPA recorded the issue as resolved.
This page summarizes the EPA's own records and does not assess whether your water is safe to drink. For the most current details, you can verify every record directly with the EPA, and contact your water system with questions.
Source: U.S. EPA Envirofacts SDWIS, retrieved October 2026. Records cover the EPA's full reporting history for these systems. Verify at EPA ECHO.