Incoming water lines: Just a like to know what this is
Usually, the 1/2" lines go to a single outlet such as a sink, tub or laundry and the 3/4" line or lines run to multiple devices. For example, the 3/4" line can feed many devices with 3/4"X1/2" tees supplying each faucet with a 1/2" supply line. This way you will usually get maximum flow at your faucet even if someone else in the home is using water at the same time.