Standard Kitchen Sink Drain Pipe Size

The standard size and setting.

Standard kitchen sink drain pipe size.

The 1 2 inch supply pipes that come to the sink each terminate with a shutoff valve and this valve is one of the two factors that determine the connector size on the faucet hose. 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. This pipe is the standard size for all kitchen sinks. However most of the bathroom sinks use 1 inch drain pipe.

Every state may have different code on plumbing and it may affect the required size of the bathroom sink pipe. A standard rule of thumb is that sewer pipes leading away from a toilet are 3 inches in diameter. These drains like bathroom and kitchen drains use a p trap which is a j shaped pipe that connects to the main drain line. It provides the right amount of flow to drain a kitchen sink during heavy use.

This size is precisely the diameter of the pipe instead of the length. Drains connect to either a 1 1 4 inch or 1 1 2 inch tail pipe. A 2 inch sink strainer fits the standard bar sink drain. All the pipes that connect to the tailpiece including the p trap assembly.

When installing a new kitchen sink drain or repairing an old leaking one you need a particular size drainpipe. The inlet must match the supply pipe and it can be a 1 2 inch female pipe thread fpt connector for galvanized pipes a 1 2 inch compression or sweat connector for.