How to Measure a Sink Drain Drainpipe J Trap & Supply Lines

Measure from the wall where the house drain pipe is to the nut securing the J trap to the sink drain pipe with a tape measure. Add two inches to the measurement and write it down on a piece of paper. This is the measurement for the rear sink drain pipe. The additional two inches is where the pipe slides into the house wall drain.

Place the end of the tape measure on the top of the nut securing the dink drain pipe to the bottom of the sink basket. This is known as the tailpipe. Measure down to the nut securing the J-trap to the tailpipe and write the measurement down.

Position the tape measure over the end of the nut securing the J trap to the sink wall drain pipe and measure to the front side of the J-trap. Write the measurement down.

Move the end of the tape measure to the top of the water supply line connecting to the faucet. Measure down to the shut-off valve and write down the measurement. Repeat for the remaining water supply line.