plumber

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One that installs and repairs pipes and plumbing.
• noun Slang An employee assigned to investigate and stop leaks of sensitive information.

from The Century Dictionary.

• noun One who works in lead; especially, one who fits lead pipes and other apparatus for the conveyance of gas and water, covers the roofs of buildings with sheets of lead, etc.

from the GNU version of the Collaborative International Dictionary of English.

• noun One who works in lead; esp., one who furnishes, fits, and repairs lead pipes.
• noun Any worker who installs or repairs piping and related equipment for conveyance of water, gas, or drainage into or out of buildings, or within buildings to fixtures or equipment using water. The type of material used for the conduits varies with the application, and may be may be of lead, iron, copper, glass, palstic, or other material.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun One who works in lead.
• noun One who furnishes, fits, and repairs pipes and other apparatus for the conveyance of water, gas, or drainage.
• noun UK In the Royal Navy, nickname for an apprentice, a boy aged 16 to 18, who is trained in technical skills at the Dockyard Schools to become an Artificer.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a craftsman who installs and repairs pipes and fixtures and appliances