Michigan § 339.6107 - Plumbing contractor, master plumber, journey plumber, or apprentice plumber; license or registration required; work not requiring license; performing activities within scope of licensure or registration.

(1) A person shall not engage in or work at the business of a plumbing contractor, master plumber, journey plumber, or apprentice plumber unless that person is licensed or registered under this article. Except as provided in subsections (2) and (3), only a licensed master or journey plumber shall perform plumbing. A licensed master plumber shall be in charge and responsible for proper installation and conformance with the state construction code. Plumbing shall not be performed unless the plumbing contractor who is responsible has obtained a permit from the state or a governmental subdivision authorized to issue permits.

(2) A license under this article is not required to perform any of the following work:

(a) Minor repair work.

(b) The installation of a building sewer or water service pipe, if a permit is secured from the responsible enforcing agency and inspections are performed. The installations shall comply with the applicable parts of the state construction code.

(c) The installation of domestic water treatment and filtering equipment that requires modification to an existing cold water distribution supply and associated waste piping in buildings if a permit is secured, required inspections performed, and the installation complies with the applicable parts of the state construction code. If the enforcing agency determines a violation exists, the responsible installer must correct it.

(d) The installation by a homeowner of his or her own plumbing, building sewer, or private sewer in his or her single-family dwelling if a permit is secured.

(e) The installation of medical gas piping, if the installation is performed under the supervision of a licensed plumbing contractor.

(3) This article does not prevent a person from performing any activities within the scope of licensure or registration under any other licensure or registration act or applicable codes for that licensed or registered professional adopted pursuant to law.