Home Drain Encyclopedia

Clogged toilets are a common household problem, although with a bit of family or roomie education and some common sense, many times they could have been avoided.

A clogged toilet or commode does not drain when flushed. Water held in the tank of the toilet flows into the bowl, but does not wash away the contents down the drain. Instead the toilet bowl and drain become backed up behind a clog of waste, and the water stays in the bowl. When this happens, do not flush again! Most toilets can hold the contents of a single tank or flush of water without overflowing, but flushing an already backed up toilet is sure to cause a disgusting mess as the sewage flows over the rim of the bowl onto the bathroom floor.

When it comes to clog prevention, all you have to do is avoid dropping certain things down the drain. Kitchen sink clogs frequently build up over time, slowly restricting water flow until eventually the drain is blocked. Other times something particular has been washed down the drain and is clogging the pipes.

Often the drain will be narrow with a screen to catch debris. If this area has been cleared, but the drain remains slow or stopped, then a clog has formed in the U-trap or even farther down the pipes. In these cases a plunger or handheld drain auger is the proper tool for the job, but some clogs can be cleared without the need for either.

Clogged floor and basement drains pose special problems.  Access to the pipes from below is restricted. Basement drains and any drain that may flow either directly into the ground or to storm drain runoff should always have backflow prevention devices installed. Backflow prevention devices work by plugging up the drain if water starts to flow the wrong way, thus preventing water backing up and flooding your basement.

Most floor drains however will be connected to pipes carrying wastewater and sewage away from the house. When this is the case, the drain will have a trap somewhere nearby along the line. In sinks, showers and tubs the trap is just underneath, but floor drains may flow horizontally some distance before meeting the gas trap. Floor drain traps are U-shaped, with pipes flowing to and from the drain meeting the U on the sides. The U itself is capped on both ends with threaded plugs, which can be removed to provide access to the pipes surrounding the trap. Floor drain traps often have only these end-caps exposed, with the pipes running below the floor. To find the U-trap for your floor drain, look nearby for two large capped end-pipes.