Collis has over 35 years of experience with wetlands regulation at the local, state, and federal levels. During his 17 years as administrator of the Wetlands Bureau at the NH Department of Environmental Services he was directly involved with the drafting and adoption of the new rules.

He has received numerous recognitions over his career most notably the 2017 Environmental Law Institute Wetlands Award for state program development and the 2019 EPA Lifetime Achievement Award.

Prior to his time at DES he served on the National Advisory Council for Environmental Policy and Technology subcommittee on Waters of the United States focusing on state assumption of permitting authority under Section 404 of the Clean Water Act. He also worked for the New England Division of the US Army Corps of Engineers during which time he assisted with the field testing of the 1987 Federal Manual for Identifying and Delineating Jurisdictional Wetlands.

He also has served for more than 20 years on his municipal conservation commission.