Licensing and island permits
Hawaii's Department of Commerce and Consumer Affairs licenses both plumbing contractors and individual plumbers, and its online search shows license status. Each county runs its own building office; on Oahu the city-county planning and permitting department covers the whole island, while Maui, Hawaii and Kauai counties handle permits for their islands.
Solar, heat pumps and corrosion
Because builders have had to put solar collectors on nearly every new house since 2010, pump, controller and collector repairs make up a big part of island service work. High utility rates push owners of older electric tanks toward heat pump units, and shoreline homes lose fittings and jackets to salt air years early. Groundwater from volcanic aquifers is warm and mostly low in minerals. Island pricing and options are covered under replacing a heater.