Invasive Species Prevention

Invasive Species

Invasive Species in Our Lakes

Our lakes are home to many different kinds of plants and animals that are good for the lake. But, some species are harmful to our lakes.


There are approximately 90 lakes and rivers in New Hampshire infested with invasive species.


Invasive species are organisms that thrive in an area where they did not evolve naturally and that cause harm to the environment, economy, or people. 

The main way invasive species spread from lake to lake  is by traveling on boats, trailers, and recreational gear that has not been properly cleaned, drained, and dried between waterbodies

Large areas of invasive plants in a lake make swimming and boating difficult and dangerous. They are expensive to control and nearly impossible to get rid of. They also reduce shoreline property values.

In 1965, the invasive plant variable milfoil was discovered in Lake Winnipesaukee—New Hampshire’s largest lake. This plant, originally from Europe and Asia, has now infiltrated approximately 75 New Hampshire lakes and rivers. A handful of other invasive plant species are also found in our lakes.

The spread of invasive plants in New Hampshire has slowed thanks to education and prevention efforts like our LakeHost program. State law prohibits the sale, distribution, growing, transportation, or introduction of 28 types of plants into our lakes.

Invasive Animals: State law also prohibits the release of many invasive animals into our lakes. 

Despite education efforts and laws, the spread of invasive animals in our lakes is on the rise. The invasive Asian clam is found in at least six New Hampshire lakes and the Chinese mystery snail is found in several dozen. Activities are not conducted to control invasive animal infestations in our lakes.

Invasive Species Prevention Initiatives

Lake Host

Clean water, healthy wildlife, and stable property values depend on a healthy lake, free of invasive species. The NH LAKES Lake Host Program is the first line of defense in keeping our lakes free of invasive plants and animals.

Clean, Drain, Dry

The Clean, Drain, Dry method is the best to minimize invasive species transfer by our Lake Hosts and NH LAKES. Learn more about this method to expedite your next New Hampshire Lake adventure!

Watercraft Cleaning Unit

NH LAKES has deployed the first waterless watercraft cleaning unit in the Northeast—the CD3 Clean, Drain, Dry & Dispose Unit! Our mobile, solar-powered cleaning unit is visiting public boat ramps throughout the state, helping boaters prevent the spread of invasive species.