Dennis was elected to the McKinleyville Community Services District Board on September 10, 2008 to fill a vacancy with a term ending November 2009. He was then re-elected in November 2009 and again in 2013 for another 4 year term. He is also a past member of the Humboldt County Planning Commission, serves on the Association of California Water Agencies (ACWA) state wide Board and the ACWA Region 1 Board as Vice President and is a lobbyist for the California Commercial Beach Fisherman's Association. He is currently serving on the Board of Directors for the Redwood Region Economic Development Commission (RREDC), started the MCSD No Drugs and Toxics Down the Drain committee and was a founding member of the Humboldt Open Door Clinic. Dennis is a local organic rancher and horse breeder and is active in the Pony Express Days, McKinleyville Rodeo Association and California State Grange.