Plumbing Glossary D

In the fourth instalment of our plumbing glossary, we’re explaining exactly what your plumber means with their industry jargon.

Today, we’ll cover the D-words.

Dam – the barrier built into a trapway of a toilet that controls the water level in the bowl

DC – Direct Current – electrical supply in which the polarity of the two wires does not change

Deionisation – process of reducing water to a non-mineral state by passing it over a bed of resins

Diaphragm – flexible membrane in a valve that deflects down onto a rigid area of the valve body to regulate water flow from the supply lines to eliminate accumulation of debris inside

Die – cutting device used to thread pipe

Dip tube – tube inside water heater that sends cold water to the bottom of the tank

Direct vent – a system that pulls outside air for combustion and vents combustion gases directly outside without a chimney

Directional jet – whirlpool air discharge unit with pivot allowing discharge path to be adjusted by user

Directional tee – tee fitting that allows direct flow in one direction by use of an internal baffle

Dishwasher tailpiece – a flanged adaptor connecting a basket strainer to the drainpipe with a dishwasher inlet

Dope – pasty lubricant used on a seal pipe thread prior to making a threaded pipe connection

Double extra strong – standard pipe weight designation, sometimes call XXH

Down head boring gimlet – a flexible cutting tip for an auger cable

Drain valve – device that allows drainage of stored contents from a water heater

Drainage tile – historically, pipe shaped clay tiles installed in below-grade trenches for gravity-rated drainage but now PVC pipes are more commonly used

Drawdown – the distance the water level drops below standing water level while pump is operating

Drip leg – a stub end pipe placed at a low point in the gas piping to collect condensate and permit its removal

Duovalve – a twin valve (hot and cold) with a single on/off lever used for washing machines

Duplex basin – an ejector pump container, large enough for two pumps, used in multi-family buildings

DWV – Drainage, Waste and Vent systems, which remove wastewater

Dynamic pressure – the pressure when the water is flowing

If you enjoyed reading this glossary, you can learn your plumbing As, Bs and Cs too.

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