Putting in plumbing and fixing plumbnig generally must be done according to plumbing and building codes to protect the the people who live or work in the buildings . Plumbing installation and repair work on residences and other buildings generally must be done according to plumbing and building codes to protect the inhabitants of the buildings and to ensure safe , quality construction to future buyers . If permits are required for work , plumbing contractors typically secure them from the authorities on behalf of home or building owners .