Boats on Dillon Reservoir get inspected for invasive species before launching

Dillon Reservoir is the big blue lake at the center of Summit County, held back by a dam and used by Denver Water. It is open for boating in the warm months, with public launch ramps at the Dillon and Frisco marinas.

Before a trailered boat goes in, it gets inspected. Colorado works hard to keep out aquatic nuisance species like zebra and quagga mussels, which can foul water systems and ruin a fishery. Inspectors check that your boat arrives clean, drained, and dry, and motorized boats and sailboats also need a state aquatic nuisance species stamp. Launching around the inspection is not allowed and can bring a citation.

Why a newcomer should care: if you bring a boat from out of state or another lake, plan for the inspection and the clean-drain-dry routine. It adds a few minutes but protects every lake you launch in. Inspection hours and ramp details follow the boating season, so they are not the same year-round.

Before launching at Dillon Reservoir, check Colorado Parks and Wildlife and the marina for current inspection rules and the ANS stamp requirement.