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Boat ANS Inspection and Decontamination
Boat ANS Inspection and Decontamination

Updated ANS Inspection Guidance

Boating is allowed in State Parks during Governor Polis's Safer at Home order. Please go boating in your local area and do not travel to go boating; visit lakes or reservoirs in your local area. 

Boaters must comply with CDPHE requirements and CPW's Aquatic Nuisance Species regulations to stop the spread of zebra or quagga mussels and other invasive species.

  • Maintain a social distance of six feet minimum when interacting with CPW staff or other people.
  • Wait for the inspector to wave you forward to the inspection station. 
  • Remain in your vehicle, set the parking brake, and turn the vehicle off.
  • If you have a green seal receipt, please keep your window closed and show it to the inspector through the window glass.
  • Follow the inspector’s instructions if they need you to get out of the vehicle and assist with the inspection. Always maintain six feet minimum between you and staff or any other people.
  • Avoid groups larger than 10 individuals or gathering with anyone that doesn’t reside in your household. Local health board guidance may limit to groups as small as four persons; please know and follow all local health board guidance.

CPW encourages people to take local and state stay-at-home orders seriously, stay home when sick, and limit travel time wherever possible, even for approved recreation. 

Find the most up to date information on how CPW is responding to COVID-19 on the COVID-19 Response page.

ANS Stamp Required in Colorado Waters

Motorboats and sailboats must have an ANS Stamp prior to launching in Colorado waters.

Boat owners are required to purchase the ANS Stamp and operators must retain proof of purchase (electronic or printed receipt) on his or her person, the motorboat or sailboat, when operating the vessel (C.R.S. 33-10.5-104.5). 

Motorboats and Sailboats from Colorado - $25.00

  • Colorado residents will purchase the ANS stamp at the time of registration. If you register/renew your vessel online or via a registration renewal postcard, the cost of the ANS stamp appears as part of your total amount due. You do NOT need to manually add another $25 to your payment for an ANS Stamp.​​
  • Motorboats or sailboats documented by the U.S. Coast Guard or otherwise exempt from in-state registration can purchase purchase their ANS stamp online at​, or at any CPW office or sales location​​.

​​Motorboats and Sailboats from Another State - $50.00 

​Funding contributes to prevention and management of ANS in the state. To learn more about the ANS Stamp, visit our Frequently Asked Questions page​Thank you for protecting our waters and contributing to conservation in Colorado!


Green Mountain Reservoir is Free of Invasive Mussels

After three consecutive years of negative testing, state and federal officials removed Green Mountain Reservoir from the positive waters list for quagga mussels. This de-listing makes Colorado a completely negative state for both zebra and quagga mussels.  

​​​​​​​​​Know the Rules for Boating in Colorado and Prevent the Spread of ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Harmful Aq​uatic Nuisance SpeciesANS Inspection Brochure cover

Mandatory - Colorado is a mandatory boat inspection state meaning that ALL trailered and/or motorized watercraft are required to be professionally inspected by state certified personnel:

  • prior to launching in any water of the state after boating in a different state,
  • upon exiting any water in the state which is positive for an invasive species, and
  • any time an inspection is requested prior to entering or exiting a water body in Colorado.

See more about the statewide effort​ to prevent the spread of zebra and quagga mussels and other aquatic invasive species.

Check out the complete list of 72 professional Statewide Watercraft Inspection and Decontamination Sites​​​​​​ in Colorado.

Boaters should take full advantage of Colorado's green seal and receipt program, which provides documentation of compliance and will reduce wait times to get through inspection station lines and get you on the water faster. All stations use green seals. However, waters that are positive for ANS use blue receipts, while waters that are negative use white receipts. For more details, visit the CPW WID Manual.

Every boater is required in regulation to Clean, D​​rain, and Dry​​ your boat, trailer and equipment every time you enter or exit any waters.  

​It is also required that boat operators remove all plants and pull all water drain plugs from the conveyance prior to leaving the lake or reservoir.  It is not legal to transport a conveyance over land with plants on board and plugs in place.

Please read the Boater’s Guide to Aquatic Nuisance Species (ANS) Inspections to educate yourself on the requirement to boat in Colorado and how you can protect our waters by helping to stop the spread of invasive species.

Latest Findings

How to Help Prevent the Spread of Invasive Species

Zebra and quagga mussels are a serious threat to Colorado waters. Invasive species such as the zebra mussel negatively influence the food chain for native fish. Zebra mussels remove major quantities of phytoplankton from the water.  Phytoplankton is food for larval and juvenile fish. To learn more about the negative effects of aquatic nuisance species, visit Western Aquatic Invasive Species and Protect Your Waters​.​


To help the Colorado Parks and Wildlife quickly identify new populations of this unwanted species please report any sightings to Elizabeth Brown, Invasive Species Coordinator.

Please contact the Invasive Species Program at 303-291-7295 with any questions about ANS or other invasive species.​