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Use of Aquatic Herbicides
To Lake Front Property Owners: please report sightings to the DEP of suspected invasive plants instead of taking action on your own. Recent news about the invasive plant Eurasion watermilfoil have led some people to take inappropriate action against valuable lake plants. These actions range from physical removal to the illegal use of aquatic herbicides.
While aquatic herbicides can be easily purchased in stores, mail order catalogs and over the Internet, people may have the misimpression that these chemicals are safe when they are not. Herbicides can be hazardous to the environment as well as the applicator. That's why applying these without proper permission is a serious legal offense. Most catalogs and other product information sheets do not mention the Maine permit requirement.
Maine requires a permit from the DEP* and an applicator's license from the Pesticide Control Board to apply aquatic herbicides (or any other pesticides) to waters of the state. Homeowners are allowed to hand-remove a swath of vegetation 10 feet wide perpendicular from their shoreline out into the lake. This will allow a place to swim and a passage for boats. To do this, an owner needs to get a "Permit by Rule" from DEP. Although a quick and simple process, PBR carries clear standards which must be met. For information about permit by rule or if you have questions, contact your nearest regional DEP office. Chapter 305 (which contains standards for various PBR activities) and PBR forms are also available on the Natural Resources Protection Act Page.
*Putting any aquatic herbicide or algicide into any waters of the state requires a wastewater discharge permit from the DEP. Applications for permits to apply aquatic pesticides are rarely approved, and successful applications usually are submitted by state resource management agencies or their contractors. Approved projects must provide for application only by licensed applicators.
"Waters of the state" means "any and all surface and subsurface waters that are contained within, flow through, or under or border upon this State or any portion of the State, including the marginal and high seas, except such waters as are confined and retained completely upon the property of one person and do not drain into or connect with any other waters of the State, but not excluding waters susceptible to use in interstate or foreign commerce, or whose use, degradation or destruction would affect interstate or foreign commerce." 38 MRSA 361-A(7)
If a seemingly closed system actually overflows to a nearby stream, pond or hydrologically-connected wetland, it is considered waters of the state.
February 2020: DEP document regarding use of herbicides on established invasive aquatic plant infestations