Recent Water Quality Standards Reviews

Recent EPA actions regarding Colorado water quality standards

  • October 29, 2020 EPA action approving revisions to water quality standards for Regulation #38 adopted August 10, 2020.
  • July 21, 2020 EPA Action approving revisions to water quality standards for Regulation #31 adopted May 11, 2020.
  • March 12, 2020 EPA Action approving revisions to water quality standards adopted January 13, 2020 of revised cadmium standards and temporary modifications in multiple segments throughout the state.
  • Oct. 8, 2019 EPA Action approving the revisions to water quality standards for Regulations #337 and #37 adopted August 12, 2019.
  • May 2, 2019 EPA Action approving LaJunta and Suncor Energy, Inc. selenium variance in Regulations #32 and #38 adopted November 14, 2016.
  • April 24, 2019 EPA Action approving the revisions to water quality standards for Regulations #32 and #36 adopted August 6, 2018.
  • April 2, 2019 EPA Action approving the discharger-specific variance for Durango West adopted August 11, 2014.
  • Feb. 27, 2019 EPA action approving revisions to water quality standards adopted January 2019 of temporary modifications to multiple segments covered by Regulation 37 and Regulation 38.
  • Nov. 6, 2018 EPA action approving revisions to water quality standards adopted as a result of the 2017 review of temporary modifications in multiple segments throughout the state and extension of the molybdenum temporary modification adopted March 12, 2018.
  • Aug. 7, 2018 EPA action approving Town of Nucla ammonia variance in Regulation 35 adopted November 14, 2016.
  • Oct. 12, 2017 EPA action approving water quality standards and revisions to Regulations 34 and 35 adopted August 7, 2017.
  • Oct. 12, 2017 EPA action approving revisions to water quality standards adopted as a result of the 2014, 2015 and 2016 review of temporary modifications in multiple segments throughout the state.
  • Oct. 2, 2017 EPA action on revisions to Regulation 31 adopted August 8, 2016.
  • Sep. 30, 2016 EPA action approving water quality standards revisions to Regulation #38 adopted August 10, 2015.
  • Sep. 16, 2016 EPA action approving water quality standards revisions to Regulations #33 and #37 adopted August 11, 2014.
  • Sep. 14, 2016 EPA action approving water quality standards revisions to Regulations #32 and #36 adopted August 12, 2013.
  • Jul. 21, 2016 EPA action on revisions to standards for three organic chemicals in the Basic Standards and Methodologies for Surface Water, Regulation 31.
  • Jul. 14, 2016 EPA action on revisions to Regulation 31 regarding nutrients.
  • Apr. 25, 2016 EPA letter requesting information about the Grand Lake clarity standard in Upper Colorado River segment 12 of Regulation #33.