The kitchen sink drain pipe should be no more than an inch from the wall. In older polished brass single hole bathroom faucet, there is a 1/4 inch tailpiece attached to the drain. The length of the drain pipe must match the size of the sink. If the drain is smaller, you should cut the existing one. The length of the pipe is determined by the diameter of the drain hole. If you need to install a new kitchen waste pipe, you should also measure the diameter of the pipe.