Is pressure reduced in a 1/2 to 3/8 inch supply line ?


With the faucet closed, the static pressure will remain the same. The faucet's valve or cartridge ports are smaller than either tubing sizes. So, even with the faucet open, the pressure should remain relatively the same.

Updated on April 11, 2018

Original Article:

Faucet Supply Line Types and Installation
By Bert Holopaw