In December, CDPHE adopted Regulation 31, a new air quality rule targeting methane emissions from municipal solid waste landfills.
What’s changing?
✅ Applies to up to 32 of Colorado’s 82 municipal solid waste landfills by targeting facilities based on waste-in-place and methane emissions — expanding regulatory reach beyond federal minimums.
âś… Establishes stricter gas collection and control requirements, ensuring methane capture is improved.
âś… Expands monitoring expectations and options (including advanced technologies).
âś… Phases out open flares in favor of enclosed systems to increase effectiveness and performance testing, and requires biofilters once combustion devices are removed.
This rule is expected to significantly reduce methane emissions while supporting Colorado’s long-term climate goals.
đź’ˇ Why it matters: Landfill operators and compliance teams may see new permitting, monitoring, and compliance obligations under the new regulation, including annual reporting of waste-in-place and methane generation rates beginning mid-2026.
