What a plumber does: Plumbers install and repair faucets, fixtures and the pipes that carry water, sewage and natural gas throughout a home. They also deal with water mains, septic tanks, laundry facilities, water heaters, sump pumps and related systems. Some plumbers can install tile and other kitchen and bath surfaces.When to hire one: You may be able to silence a running toilet or fix a leaky showerhead on your own, but more complicated plumbing jobs require qualified help. Unless you have extremely thorough experience and training from a qualified plumber, always use a pro for behind-the-walls work — the risk of water damage (or worse) isn't worth the DIY cost savings. Remodeling and new-construction jobs call for a plumber as well.