A maintenance plumber is a role within the plumbing profession that focuses on the upkeep of large water systems. In this career, you are usually employed by larger organizations to maintain the plumbing systems of large facilities or campuses. Your responsibilities depend on the type of building you are maintaining, but your basic duties are to maintain, repair, or install gas, water, irrigation, or sewer systems. Generally, the systems on which you work as maintenance plumber are designed for large-scale use by many individuals. This differs from plumbers who operate on individual systems in homes.