Working to reduce harmful emissions across all sources, the California Air Resources Board (CARB) approved updates to its Landfill Methane Regulation (LMR) that will enable quicker detection and repair of methane leaks at landfills, improve monitoring and reporting, and facilitate stronger action for recurring issues. Methane, generated from the breakdown of waste, is a potent greenhouse gas, and landfills are the second largest source of methane in the state.
Findings from research and the development of new technologies provided opportunities to update the regulation to improve the collection and control of methane emissions at California’s 188 landfills subject to the LMR.
“This is another example of California’s leadership in reducing emissions and harmful climate-warming pollutants across all sources. With these updates, California will be able to more efficiently and effectively monitor methane sources to detect and remedy leaks quickly,” said CARB chair Lauren Sanchez. “Regardless of what’s happening in Washington, CARB will press ahead on our mission following the science and using the latest research and technology to protect Californians from climate change and harmful air pollution.”
Updates include a greater role for the use of advanced technology including satellite imaging to detect methane leaks across the landfill, and other methods suited to monitoring the active area of a landfill and other areas that are unsafe to access by foot. Emissions reductions will also come from improved gas collection system performance; more frequent monitoring and quicker resolution when a leak is detected; stronger action for recurring issues and improved reporting for enhanced transparency and oversight. The LMR updates will also reduce co-pollutants like toxic air contaminants, volatile organic compounds and odorous compounds.
Amendments will apply to active, inactive and closed landfills operated by both public and private entities.
In addition to CARB, landfills are regulated by federal, state and local agencies. The LMR allows cooperative agreements between CARB and the air districts, which allow the air districts to implement and enforce the regulation and assess fees to cover costs. Currently, 22 local air districts are implementing and enforcing the LMR.
Published December 2025