The basic principle of the floor drain is simple: gravity moves the water out of the house. The floor drain is generally installed at the lowest position where the ground slopes. The drain pipe drains the water into the sewer system, and then the water is taken away together with the waste water in the house and the drain pipes of other water inlet systems.

The cleaning plug is a component that most floor drains have. It is a rubber plug, fixed in place by bolts and wing nuts. The cleaning plug is an opening inside the floor drain and can be used to remove blockages in the pipeline. It usually remains blocked. The plug may rust and be damaged due to corrosion. When this happens, the plug must be replaced. In some floor drains, cleaning will bypass U-shaped traps, so the plug must be kept in good condition to prevent sewer gas from entering the home.

The drainage elbow is an important part of the floor drain. The traps used in floor drains are similar to those used in kitchen and bathroom fixtures. The drain pipe is immersed in a U-shaped pipe, which is always filled with water, whether it is flowing or stationary. Water-filled traps prevent toxic sewer exhaust gas from flowing back into the house. Drains with traps must also be ventilated to maintain a neutral air pressure in the system and allow water to flow freely.

Dredging floor drains is no different than dredging other wastewater pipes. Sometimes a plunger can be used to clear a blocked floor drain. In other cases, it may be necessary to use a cleaning plug. More advanced methods may require plumber skills and equipment. In some cases, inserting the water pipe as far as possible into the drain pipe and opening it may be enough to flush out debris.