Kitchen Sink Drain Pipe Size

The drainpipe threads onto this pipe with a connector.

Kitchen sink drain pipe size.

The kitchen drainpipe connects to the drain under the sink. Drains connect to either a 1 1 4 inch or 1 1 2 inch tail pipe. For instance the minimum pipe diameter for a washing machine drain is pipe with a 1 1 2 inch diameter. All the pipes that connect to the tailpiece including the p trap assembly.

The drain has a threaded pipe sticking out below the lock nut that secures the drain to the sink basin itself. A single trap can service more than one sink but adjacent drains cannot be farther apart than 30 inches. The horizontal pipes connect to the trap with a double wye tee which has two y shaped inlets and one outlet. Compare the fixture to the minimum sizes of drainage pipe by fixture table.

These drains like bathroom and kitchen drains use a p trap which is a j shaped pipe that connects to the main drain line. Some older sinks may have drains that connect to a 1 1 4 inch tailpiece but most modern drains have a 1 1 2 inch outlet. Since the pipe is 1 1 2 inch in diameter kitchen drainpipes are also 1 1 2 inches in diameter. Unlike drain pipe on the shower or tub that will be connected to two units this sink drain pipe will be connected to only one unit on the drain line.

Kitchen sink is commonly connected up to two units or three units for one with disposer.