A kitchen sink is common in every home, and this fixture is the jack-of-all-trades in the kitchen as a center for hand washing, wastewater disposal and water supply for cooking and other kitchen appliances. Due to its many roles, the kitchen sink assembly is generally more complex than a bathroom sink, and a basic understanding of the lines and parts of your kitchen sink can prove helpful for at-home plumbing repairs.
The faucet and handles are the control equipment for turning water on or off for use in the kitchen sink. Many modern kitchen sinks use a single faucet handle that can be moved forward or backward to control flow and left or right to control temperature. The faucet itself can swivel to allow water distribution in both sink bowls.
Some kitchen sinks feature a sprayer hose to allow for direct water spray for hand dishwashing or other applications. The hose is attached between the faucet and water supply with a connector valve that controls where water is directed when the trigger of the sprayer is depressed. The faucet will not run when the sprayer is in use.
Under the sink, hot and cold water supply lines connect to the faucet. Single handle sinks contain a valve that regulates temperature, whereas dual handle sinks connect directly to the respective line. Each line features a shut-off valve so water supply can be interrupted for emergencies or repairs.
The plumbing pipes that connect from the drain transfer used water to the sewer, and a section of the wastewater line controls sewer gas from entering the home through the drain. The bending shape of the trap allows a small amount of water to remain in the pipe, trapping air from entering. After a long vacation or months of not using the sink, homeowners may notice the smell of sewage coming from the drain, but a simple fix is to run water for a few minutes to allow water to push out air and seal the trap again.
Garbage disposal units are generally attached to one of the drains in a dual bowl kitchen sink. This appliance pulverizes food waste so it can safely wash down the wastewater line. The garbage disposal drains into the waste line above the trap, so wastewater can exit either sink.
The supply and waste lines run from the kitchen sink plumbing to the dishwasher. The supply line is connected to the hot water supply, and the wastewater returned from the dishwasher generally connects to an air gap, or trap, in the sink before connecting to the waste line through the garbage disposal unit. The dishwasher air gap keeps wastewater from backing up into the dishwasher.