Courtesy Boat Inspections

Video #1 - DEP’s invasive aquatic biologist John McPhedran demonstrates how to do a thorough boat inspection in under 3.5 minutes.

Video #2 - Developed for Maine’s Courtesy Boat Inspection Program inspectors, this 8 minute video discusses the importance of protecting our lakes and shows how to interact with boaters while walking them through an inspection of their boat.

Related pages: For information on starting your own Courtesy Boat Inspection as well as guidance on training and financial aid, contact Lakes Environmental Association. (off-site)


Maine has 2,400 lakes greater than 10 acres in size with less than 1% of these infested with invasive aquatic plants. Maine's primary invasive aquatic species prevention effort is the Courtesy Boat Inspection (CBI) program. The CBI Program completed its 19th year in 2019. The purpose of these voluntary inspections is to reduce the spread of invasive aquatic plants (IAP) to Maine waters by boats, trailers, and associated equipment.  Trained Courtesy Boat Inspectors discuss with boaters the risk posed by IAP, show boaters how to inspect and remove vegetation from boating and fishing equipment, and urge boaters to inspect before each time they launch and after each time they retrieve their boat.

The Maine Department of Environmental Protection (DEP) contracts with Lakes Environmental Association in Bridgton to provide inspector training and assist DEP with grant oversight and communications.  

Courtesy Boat Inspection Results Summary - 2019 Season

Maine’s 2019 Courtesy Boat Inspection program had another busy season, recording 89,860 courtesy boat inspections. To achieve this, 44,840 inspection hours were logged in 2019, roughly equivalent to 22 full-time employees.  Boats were inspected both entering and leaving the water with most inspections (59%) conducted on boats entering. Maintaining this high level of prevention effort is a tremendous achievement for local and regional groups running the inspection programs. 

BASS clubs participating in club tournaments are required to conduct inspections as a condition of their permit from the Maine Department of Inland Fisheries and Wildlife.  In 2019, 51 bass clubs conducted 6,963 inspections of member boats during club tournaments.

2019 Courtesy Boat Inspection Statistics

  • 89,860 total inspections on both motorized and non-motorized boats
  • 99% of the motorized boats had the Lake & River Protection Sticker
  • 123 launch sites on 94 waterbodies had CBIs
  • 15 infested waterbodies had a CBI Program
  • 2,901 inspections (3.2%) yielded plant fragments – native or invasive
    • of these intercepted plant fragments, 74 (2.6%) were “saves” (invasive plants) found primarily on boats exiting infested waters
  • 53 organizations CBIs – plus 51 bass clubs inspected member boats at their permitted tournaments
  • 620 courtesy boat inspectors (paid and volunteer) worked a total of 44,840 hours

Inspections have remained about 80,000 annually since 2012 and the 2019 season produced an all-time high of 89,860 inspections as the graph below shows.



Courtesy Boast Inspection Yearly Totals

Maine requires that all boaters using inland waters purchase and attach a Lake and River Protection sticker. For Maine registered boats, this is part of the annual registration sticker. For non-resident boats, the sticker must be purchased separately.

The total of motorized boats with Lake and River Protection Stickers = 89%
Maine boats: 94%
Non-Maine boats: 72%

When inspectors asked boaters the last lake they visited, 1,077 said they were on an out-of-state lake and 16,581 said they were on a different Maine lake. The charts below show the percentage of infested vs. uninfested lakes for each group.

Confirmed "Saves" in 2019

Most boats found with invasive plants before launching had previously been on the same lake they were entering. However, two boats came from out-of-state infested lakes: Lake Bomoseen, VT and Candlewood Lake, CT.

For more information concerning Maine's Courtesy Boat Inspection Program, visit the Maine DEP's Invasive Aquatic Species Program website at or the Lakes Environmental Association website at, or e-mail DEP at