Chaffee County commissioners were told July 16 that a draft change to Colorado Department of Public Health and Environment (CDPHE) Regulation 31 would lower the thresholds that trigger landfill gas monitoring and mitigation and require earlier, more frequent monitoring than federal rules, potentially forcing installation of gas collection systems at the county landfill.

The county's landfill consultant, Victoria (Sanborn, landfill engineering consultant), told commissioners the site already is just above a draft threshold the state uses to determine which sites must do quarterly surface-emissions monitoring. "You will do an analysis of what kind of emissions you all have," Victoria said, and "as soon as you have 1 hit of any kind, you will be required to install a gas system." Heather (Sanborn, landfill engineering consultant) added that the regulation in draft is more stringent than federal rules: "They've tried to mimic the federal regs, but then made it a lot more stringent."

Why it matters: the draft rule would both expand the number of landfills subject to frequent surface-emissions checks and raise how often operators must check an installed system. Consultants said the draft would change weekly monitoring where federal rules require monthly review, and it would use a much lower surface-reading threshold than the 500 parts per million (ppm) that often triggers federal action; the draft's example limit cited by consultants was 25 ppm. Consultants also flagged third-party remote methane detection platforms such as Carbon Mapper as additional triggers that could require a county response.

Costs and operational impacts were a central focus. Sanborn's initial financial estimate for a first-phase gas collection system for the county was about $1,250,000, with additional annual expansion and ongoing operation-and-maintenance costs thereafter. Victoria said construction to expand a system would likely occur every year, and Heather said regulators would expect more staff or a dedicated consultant to manage weekly monitoring under the draft rule. County staff noted that a post-closure operating window for a system typically extends decades: a consultant said systems are often required to operate at least 30 years after closure, and county staff observed the landfill’s final closure horizon is not expected in the county’s lifetime (comments referenced a multi‑decade to century planning timeframe).

Commissioners and staff discussed next steps: the state is soliciting public comment and has a published deadline for submission in early August. County staff directed consultants to prepare more detailed cost and technical background and to coordinate draft comment language for the county to consider; staff said the county will bring a draft comment back for discussion at the Aug. 4 work session so it can be submitted before the state's Aug. 5 deadline. No formal regulatory decision was made at the meeting — the board's action was to gather more analysis and prepare coordinated county comments.

Consultants and staff emphasized that the draft regulation is statewide and not targeted at any single site: as Heather said, "They're not picking on you over anybody else. It just happens that you fall into this into their standards that they're setting." Commissioners pressed for documentation and background science; consultants agreed to provide federal- and state‑level regulatory documents and technical background to the county.

The county's consultant team highlighted additional specific items the draft would change compared with existing federal practice: weekly (rather than monthly) monitoring of operating systems; lower surface-monitoring thresholds (the draft cited 25 ppm for the grid average in discussion); and new cover-layer requirements that could increase annual landfill operating costs. Consultants also said remote detection platforms and satellite data would be incorporated into oversight practice and could force local responses if elevated methane signatures were identified.

The county will continue coordinated work with neighboring counties and statewide associations to prepare comments and to pursue clarifications from CDPHE on implementation timelines, permitting timelines for flares or alternative beneficial‑use projects (for example, RNG or electricity generation), and the state's capacity to provide timely permit reviews for required gas systems. County staff and consultants said they would return to the commissioners with detailed cost estimates and sample comment language ahead of the state's comment deadline.