Mary Lou spent over 38 years working at the U.S. Environmental Protection Agency at both EPA Headquarters and Region 10. Mary Lou served on the EPA team that created the National Estuary Program, and worked with Congress to include Section 320 as a part of the 1987 amendments to the Clean Water Act. As a part of that work, Mary Lou provided leadership to ongoing and incoming National Estuary Programs throughout the US. Mary Lou moved to the Pacific NW in 1993 and began work on watershed restoration and tribal fish consumption throughout the Columbia River Basin. Mary Lou served as the US EPA lead for the Columbia River Basin and in that role worked on critical water quality issues including water temperature and toxics. To address toxics and building on the collaboration model from the NEP, Mary Lou created a diverse Columbia Basin wide collaboration including Tribal, federal, state, and local governments; agriculture; industry; NGOs; and others to work together to reduce toxics in the fish and water in the Basin. This collaboration led to the passage in 2016 of Section 123, the Columbia River Basin Restoration Program as an amendment to the CWA. In 2021, Mary Lou provided leadership to bring $79 million in Bipartisan Infrastructure funding to fund toxics reduction grants throughout the Columbia River Basin.
After retiring from EPA in 2023, Mary Lou now serves on a number of NGO Boards to provide to support to community based efforts. She assisted the Grand Ronde Tribe (in partnership with Water Policy Pathways) in the development of a February 2025 Comprehensive Toxics Reduction Assessment for the Grand Ronde Tribal Community, and led an agricultural and household hazardous waste Toxic Take Back Event on the Grand Ronde Reservation in April 2025. Mary Lou works part time for Jacobs Engineering as a Senior Advisor on Columbia River Basin water quality work efforts and working with Tribal Governments.