Arapahoe County staff outline proposed septic (OWTS) regulation updates, set public hearing next month

Arapahoe County environmental health staff presented a detailed study-session briefing on proposed updates to the county's on-site wastewater treatment system (OWTS) regulations that would align local rules with the Colorado Department of Public Health and Environment's (CDPHE) updated Regulation 43 and preserve local permitting authority.

Steve (presenter) said the county must adopt local regulations consistent with state updates and noted several proposed opt-ins and technical changes. "These responsibilities come directly from the OWTS Act," he said, adding that adoption by the local board will keep the county's permitting authority; if the county does not adopt, CDPHE would assume implementation. Staff flagged a target effective date of May 7 (to align with the 45-day effective-date requirement) and said the CDPHE deadline for local adoption is June 15, 2026.

Key technical and programmatic proposals include: - A secondary safety feature installed below septic tank lids to prevent people or pets from falling in. - Updated rock and soil tables (affecting mountain jurisdictions) and a new higher-level treatment option (including disinfection) to reduce system footprint. - A residual-head (squirt height) test for pressure distribution systems to verify effluent reaches field termini. - Required effluent filters on all new tanks and tanks replaced during repairs, with alarms on pressurized systems to notify owners of maintenance needs. - Conditional licensure for installers that gives contractors time (about 180 days) to complete required certification, and an option to handle minor variances administratively (with larger or contested variances coming to the board).

Steve said the county will continue transfer-of-title inspections and an oversight program for higher-level treatment systems and nonpressurized dispersal systems. He also said the county plans to require professional qualifications for soil evaluations and clarified that some opt-ins being adopted elsewhere are not proposed for Arapahoe County for safety or practicality reasons (for example, leaving soil test pits open is not proposed because of safety concerns).

Staff reported limited public attendance during the outreach period but active engagement with industry stakeholders and installers. Steve agreed to provide comparative fee information from other counties as the county develops a fee structure permitted under statute.

Next steps: the board will hold a public hearing next month on the final draft and then consider adoption; staff expect to bring a final draft for consideration and noted they do not anticipate large substantive changes.