Reg. 43 - On-site Wastewater Treatment Systems (OWTS)

        en español
two side by side black pipelines embedded in dry earth

The Water Quality Control Commission adopts rules for On-Site Wastewater Treatment Systems (OWTS) called Regulation 43. Once the commission adopts rules, every county health department in Colorado must adopt detailed regulations for small wastewater treatment systems that comply with the commission's rules and the OWTS Act.

The division implements Regulation 43, which governs on-site wastewater treatment or septic systems. Regulation 43 sets minimum standards for how small wastewater treatment systems in Colorado (treating 2,000 gallons of wastewater or less per day) should be located, designed, constructed, and used. County health departments use these minimum standards to create rules, including permit application requirements, issuing permits, system inspection, and system maintenance.

As part of the regulatory update, the division is inviting all regulators and practitioners within the onsite wastewater industry and the general public to join the Regulation 43 workgroup and participate in this process.

How to get involved


The division holds meetings to discuss possible changes to the regulation. The division plans to end sessions in August 2024, followed by a rulemaking hearing by the commission in spring 2025.

 Sign up to receive notifications about this effort, and scroll down to select "Reg 43 - On-site Wastewater Treatment System."


After the meetings conclude, a copy of the recording, chat, presentation, and other meeting materials will be stored in this public folder.

Scheduled MeetingsRegister to attend here

  • Tuesday, October 10, 2023 | 1:00 to 4:00 p.m.
  • Tuesday, October 31, 2023 | 1:00 to 4:00 p.m.
  • Tuesday, November 21, 2023 | 1:00 to 4:00 p.m.
  • Tuesday, December 12, 2023 | 1:00  to 4:00 p.m.
  • Tuesday, January 9, 2024 | 1:00 to 4:00 p.m.

Previous Meetings

  • August 29, 2023 | 1:00 to 4:00 p.m.
  • September 19, 2023 | 1:00 to 4:00 p.m.


For more information, please contact: