California Adopts Stringent Landfill Methane Rule: Updated to Require Faster Leak Response Times, More Monitoring of All Sites, and Third-Party Technology Verification

    

     The State of California recently completed a three-year evaluation process culminating in a final landfill gas emissions regulation that is considered to be the most stringent in the U.S. The Landfill Methane Rule was first adopted in 2010. The new provisions are an upgrade to that rule. The California Air Resources Board (CARB), the agency in charge of the rule, noted that the changes are in line with state targets intended to lower methane emissions 40% below 2013 levels by 2030.

     Jacob Wallace of Waste Dive points out that California was the first state to specify methane emissions from landfills rather than all air emissions, as other states have done. Landfills emit CO2, volatile organic compounds (VOCs), and other air pollutants. Methane, however, is the major component of landfill gas, followed closely by CO2. Requirements for the installation of gas collection and control systems earlier in a landfill’s life and new trends such as the use of drones to monitor gas leaks are becoming increasingly common. The California rule covers 188 landfills and requires 153 of them to install gas collection and control systems. CARB estimates that local governments will see compliance costs of about $6.1 million annually, which can be recovered by raising fees.

     The new rule requires landfill operators to fix leaks faster when third-party monitoring detects them. The state was the first to use drones and satellites to monitor landfill emissions. Wallace notes:

“Reacting to new technology in the market, the rule would also require using “handheld or drone-mounted laser scanners to identify leaks in inaccessible areas that are currently excluded from monitoring.” The rule seeks to encourage the use of continuous wellhead monitoring technologies by reducing regulatory barriers and clarifying certain language as well.”

     The rule updates are expected to go into effect in 2027. The chair of CARB, Lauren Sanchez, attended the COP30 meeting in Brazil with Governor Newsom and noted that methane emissions continue to be a major topic.

“This is an especially exciting moment to take action on this area of work, because we have technologies to now help us detect, measure and address methane emissions,” Sanchez said in her opening statement. “When combined with strong regulations, these technologies can help us make real progress on cutting pollution here and now.”

     The upgraded rule includes new monitoring requirements for landfills with and without gas collection and control systems. Landfill operators will also be required to respond to detected leaks via third-party technology verified by CARB — including the agency’s own California Satellite Methane Project.

     A summary of the rule's changes is given below:

References

 

California adopts most stringent landfill gas rules in the country: The three-year process culminated in a final regulation that sets some of the most stringent rules in the country for landfill gas control systems. Jacob Wallace. Waste Dive. November 21, 2025.  California adopts most stringent landfill gas rules in the country | Waste Dive

California’s landfill methane rule proposal tightens gas rules: The proposed rule would tighten restrictions for landfill gas collection and control systems and expand the role of remote monitoring programs. Jacob Wallace. Waste Dive. September 25, 2025. California’s landfill methane rule proposal tightens gas rules | Waste Dive

Public Hearing to Consider the Proposed Amendments to the Regulation on Methane Emissions from Municipal Solid Waste Landfills. Staff Report: Initial Statement of Reasons. Date of Release: September 23, 2025. Scheduled for Consideration: November 20, 2025. California Air Resources Board. Landfill Methane Regulation 2025 ISOR