Contractors Are Not Licensed - Homeowner Beware!Although home improvement contractors are not licensed or regulated by the State of Maine , architects, engineers, electricians, plumbers, oil burner technicians, manufacturers, dealers and installers of mobile and modular homes are required to be licensed
Written Contracts Are Required: by Maine law contractors and subcontractors performing all home construction and home improvement projects over $3,000 are required to provide a consumer with a written contract with a specific provision that prohibits payment up front of more than one third of the contract price.
Building Codes: Because of many towns and cities have adopted building codes and enforced them, a homeowner should talk to his town's code officials before starting Plumbing project.
https://www.maine.gov/ag/consumer/housing/home_construction.shtml