Recent EPA actions regarding Colorado water quality standards
November 25, 2024 EPA action approving revisions to water quality standards adopted on August 21, 2024 for Regulations 31 & 33.
November 25, 2024 EPA action approving revisions to water quality standards adopted on August 21, 2024 for Regulations #32-38.
April 30, 2024 EPA action approving corrections to water quality standards for Regulation #38 adopted on February 12, 2024 (with no action).
January 4, 2024 EPA action approving revisions to water quality standards adopted on October 10, 2023.
July 12, 2023 EPA action approving revisions to water quality standards adopted on April 12, 2023 (with no actions).
December 8, 2022 EPA action approving revisions to water quality standards adopted on August 8, 2022 and October 11, 2022 (with no action and recommendations).
May 7, 2021 EPA action approving revisions to water quality standards adopted February 8, 2021 of discharger-specific variances to segments throughout the state.
May 7, 2021 EPA action approving revisions to water quality standards adopted February 8, 2021 of temporary modifications to multiple segments throughout the state.
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 #33 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.
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.
