Manifold

A manifold is a fitting assembly—usually brass or plastic—that takes a single inlet and splits it into several numbered outlets, each with its own isolation ball valve. In modern plumbing, manifolds are the backbone of PEX and hydronic systems, letting you run individual lines to fixtures or zones without daisy-chaining and without cutting into supply lines to service one outlet.

In the field, manifolds simplify rough-in significantly. Instead of running parallel 3/4" copper to multiple bathrooms, you run one 3/4" line to the manifold in a central location—usually in a utility closet, basement, or under a vanity—then fan out 1/2" PEX to each fixture. Each outlet valve lets you shut off a single fixture without affecting others, which saves callbacks and makes troubleshooting obvious.

Choose your manifold based on flow demand and outlet count. Residential hot-water manifolds typically handle 3-5 outlets; zones or larger homes need larger units or multiple manifolds. Undersizing creates pressure drop and weak fixtures downstream. Always install isolation valves on the inlet side and consider backflow prevention depending on local code and system design.