Most of the time. Property owners may perform building related trades on property they own and occupy. Property owners may personally perform mechanical, electrical and plumbing on property they own and occupy.
Exceptions:
Rental Properties - Owners may perform building trade work. However, all plumbing, electrical & mechanical work shall be performed by a licensed contractor.
Intend to Sell Property - Owner must be state license if performing work on more than one property in a two-year period. All other trades require a licensed contractor.