What Is the Trapway Size on Kohler Toilets?

The trapway is the drain path inside the toilet that water follows to reach the floor's waste outlet. The trapways on Kohler toilets are designed larger than the minimum requirements set by the American National Standards Institute, or ANSI. In general, this larger size makes for improved flushing performance.

Kohler One-piece and Two-piece Toilets

All Kohler one-piece toilets and the company's Wellworth two-piece gravity-flush toilets have trapways with a diameter of 2 inches. The trapways in all of these toilets are also glazed, greatly assisting the passage of waste and water through the trapways. Although ANSI minimum standards permit a trapway size that allows an object the size of a golf ball to pass through, Kohler's 2-inch trapways allow passage of an object the size of a handball.

Kohler Power Lite and Pressure Lite Toilets

Kohler's selection of toilets that use "power lite" and "pressure lite" flushing technology have even larger trapways -- 2 1/8 inches in diameter. Like the trapways in Kohler's other toilets, these trapways are also glazed. The pressure-assisted flushing of the "pressure lite" toilets, and also the pump-powered flushing of the "power lite" models, pushes the water with more force than is used in gravity-flush models. This means that these toilets need even less water to efficiently travel through the larger trapway without clogging.

ANSI Standards

The American National Standards Institute promotes and facilitates voluntary consensus standards but does not actually set these standards itself. The minimum trapway size that is allowed by ANSI standards is 1 1/2 inches. However, most toilets usually have a trapway between 1 3/4 to 2 inches. The trapway size of a toilet is an essential feature, because a smaller trapway inhibits the smooth flow of waste, especially when a smaller amount of water is used on each flush.

Locating Kohler Trapways

If you look at the back of the toilet base on a floor-mounted Kohler toilet, you can sometimes see a curved outline in the toilet's china surface. This outline shows you the path that the trapway inside the toilet follows. The trapway connects the toilet's drain in the bottom of the bowl to the closet flange on the bathroom floor. In addition, the curved toilet trap holds water between flushes, providing a seal against sewer gases entering through the toilet bowl.