In a home-run (or homerun) system, every fixture has a dedicated PEX line that runs directly back to a central manifold near the water heater and main supply. Unlike trunk-and-branch plumbing, there are no tees or shared lines. The result is nearly instant hot water delivery, no cross-fixture pressure drops, and individual shutoffs for every fixture at the manifold.

1/2" PEX is standard for most individual fixture runs (sinks, toilets, dishwashers). Use 3/4" PEX for showers, tubs, or any fixture requiring more than 2.5 GPM. The manifold header is typically 3/4" or 1" depending on the number of ports.

Each home run typically needs exactly two fittings: one at the manifold port and one at the fixture shutoff valve. This is a major advantage over trunk-and-branch systems, which have many tees and elbows that can fail over time. Fewer fittings also means lower friction loss.

Most manufacturers and codes do not impose a maximum horizontal run length for PEX in residential applications. However, long hot water runs (over 50–80 feet) will result in significant wait time for hot water. Runs over 100 feet may benefit from a dedicated recirculation system to deliver hot water on demand.