Signs That the Toilet Flange Is Not Sealed

Updated July 11, 2018

A simple and effective plumbing part secures a toilet to the waste pipes, terminating the pipes with a glue-on fitting called a toilet flange. It has a metal ring around it that plumbers screw to the floor under the toilet, and they secure the toilet to it with bolts. A wax ring seals the toilet to the flange, but this seal sometimes breaks, producing noticeable symptoms.

The Toilet Flange

A toilet flange is a metal ring with a small length of plastic pipe protruding from one end. The pipe fits into the toilet waste pipe and is secured to it by glue. The rim of the metal ring has three holes for screwing it to the subfloor and it has two slots into which the toilet bolts fit. Before the plumber sets the toilet on top of the flange and secures it with the bolts, he places a doughnut-shaped wax ring into the opening. The ring compresses against the toilet when the bolts are tightened, forming a seal.

Causes of a Leaking Flange

The toilet flange itself rarely leaks, but the wax ring may for several reasons. If the flange is set too far below the surface of the subfloor, the ring may not make contact with the bottom of the toilet, or may not compress sufficiently. Conversely, if the flange is set too high, the toilet may not make contact with the floor and may rock, breaking the wax ring seal. The wax ring may also simply wear out with age. When the wax seal breaks, water will spill out from underneath the toilet when you flush it.

Signs of a Leaking Flange

The most obvious sign of leakage from a poorly sealed flange is visible water around the base of the toilet. Another obvious sign is sewer smells in the bathroom. Less obvious indications are wet floorboards or mould around the base of the toilet, water dropping from the ceiling below the toilet or a rocking toilet. The toilet may be rocking because the bolts are loose or the flange is too high or corroded. Any of these conditions can cause a leak that will saturate the subfloor, make it spongy and cause the toilet to rock even more.

Fixing the Leak

When you notice signs that the flange is leaking, you should correct the problem before the water does any more damage to the subfloor. The repair requires removal of the toilet. If the flange is set too low, you can raise it by adding a flange extension or by replacing the wax ring with a thicker one. If it is set too high, you can often add shims to support the toilet. Give the floor plenty of time to dry if it is wet, and always replace the wax ring with a new one before you reset the toilet.

Cite this Article A tool to create a citation to reference this article Cite this Article

About the Author

Chris Deziel has a bachelor's degree in physics and a master's degree in humanities. Besides having an abiding interest in popular science, Deziel has been active in the building and home design trades since 1975. As a landscape builder, he helped establish two gardening companies.