Plumbing Terminology - G

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Garbage Disposal

A garbage disposal is an electrically motorized kitchen appliance inside a kitchen drain that grinds waste food and mixes it with water before disposing of it through standard plumbing drainage pipes.


A gasket is a flat device that is usually made out of fiber or rubber. In the plumbing industry gaskets are used to provide a watertight seal between various metal parts or joints.


Gelcoat is a colored, polyester-resin material applied to the surface of a molded part. The gelcoat hardens to a smooth, durable form and becoming an integral part of the laminate. Fiberglass pools and spas usualy have gelcoat finishes.

GPF - Gallons Per Flush

GPF stands for Gallon per flush, generally the toilet's gallons per flush are printed on the porcelain behind the toilet seat. New toilets, per federal law, are only allowed to deliver 1.6gpf or less. In many years past, toilets flushed as much as 7-8gpf. 

At first, manufacturers tweaked the valves and floats in the tank to reduce the water used without making any changes to the tank or bowl. The two most common adaptations were to install a flush-valve flapper which closes before all the water escapes the tank (early-close flapper) or to install a plastic bucket, or toilet dam, which retains some water in the toilet tank behind the dam, thus lowering the volume of flush.

Gravity-Flush System

A Gravity-Flush System uses the natural weight of the water in the tank to generate enough pressure to flush a toilet. The water pressure forces the water from the tank down into the toiletbowl, then through the S-shaped trapway. A siphoning action completes the flush. This flushing system is quieter than the pressure-assisted system, simple, and requires less maintenance than other, more complex flushing systems, but can clog up.

Gray Water

With gray water is meant the household water recycled from sinks, bathtubs, washing machine and showers. The grey water is then among other things used to water the landscaping.

Grease Trap

Grease traps (also known as grease interceptors, and grease recovery devices) are plumbing devices designed to intercept most greases and solids before they enter a wastewater disposal system.