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WH – White finish

Wall Thickness – The thickness of the tubing wall.

Wash-down Water Closet – Water closet having a siphon trapway at the front of the bowl, and integral flushing rim.

Waste Arm Drain – An extension pipe, usually to extend a sink drain into a wall.

Waste & Overflow Drain – An assembly for a bathtub. The outlet at the top removes the overflow water during tub filling and the drain at the bottom removes wastewater when the tub is drained.

Waste Plug – Drain stopper on a bathtub drain.

Waste Shoe – Bathtub drain assembly.

Waste Stack – See Soil Stack. The vertical main pipe in a drainage system, extending one or more stories.

Waste Closet / WC – A toilet.

Water Hammer – A loud banging noise caused by the hydraulic shock of suddenly shutting off a water supply, where water moves against the side of containing pipe or vessel.

Water Hammer Arrestor – A device installed near a fixture to absorb the hydraulic shock caused by a sudden shutoff of water.

Water Hose Power (WHP) – The calculated horse power produced by the pump using the formula WHP = head x gpm/3960.

Water Service Pipe – The pipe from the water main or other sources of potable water supply to the water-distributing system of the building served.

Water Spot – Water surface in the toilet bowl once the flush is completed.

Water Table – Level below the earth’s surface at which the ground becomes saturated with water.

Waterway Fitting – A channel through which water can flow; connects water heater to inlet and outlet lines.

Watt – A unit of electrical energy or power. One ampere x one volt equals one watt.

Watt Density – Amount of watts concentrated per square inch of element blade surface area.

Wave Washer – A washer, common in drain linkages, which provides pressure against a ball or other mechanism even when the opposing nut is not fully tightened.

Weak Well – Weak well application occurs when the pump lowers the water level in the well faster than the well can replenish itself.

Weir – A long notch with a horizontal edge, as in the top of a vertical plate or plank, through which water flows, used in measuring the quantity of flowing water.

Well Casing – A steel or plastic pipe inserted into a drilled well to prevent dirt and debris from contaminating the water.

Wellpoint – A pipe fitted with a driving point and a fine mesh screen used to remove underground water. A complete set of equipment for drying up ground including wellpoints, connecting pipes and pumps.

Wet Vent – Drain or waste pipe that also acts for one or more fixtures on the same line.

Whirlpool Tub – A bathtub with circulation jets in various spots throughout the tub that provide therapeutic massaging action.

Widespread – A style of bathroom lavatory faucet having separate spout and handles, usually 8″ from center of handle to handle.

Working Pressure – Maximum pressure of the operating system permissible.

Working Water – Water used in a home for most general purposes including bathing and laundering.

Wrought Copper Fittings – Plumbing fittings used to connect copper tubes made of mechanically worked and toughened copper as opposed to an as-cast brittle copper.

Wye – A Y-shaped fitting with three openings used to create branch lines. Allows one pipe to be joined to another at a 45 degree angle.


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Source: “Plumbing Terms” Standard Plumbing Supply. 11 Sept. 2008