Short definition
A reducing bushing is a fitting that inserts into a larger female fitting (tee, coupling, valve) and provides a smaller female outlet on its own end. Available in threaded (galvanized, brass, black iron), solvent-weld (PVC, CPVC, ABS), and sweat (copper) variants — matched to the existing fitting’s joining method.
What it is
A bushing solves a sizing problem without replacing the host fitting. If you have a 3/4-inch tee but need a 1/2-inch branch off one outlet, a 3/4 × 1/2 reducing bushing screws or solvents into that outlet and converts it. The bushing’s outer threads / socket match the host; its inner threads / socket are the new smaller size.
Hex bushings include wrench flats on the body; face bushings sit flush.
Common variants and what a bushing is not
- Bushing vs. reducer. A reducer is a stand-alone size-change coupling; a bushing inserts inside an existing fitting.
- Bushing vs. adapter. An adapter changes joining method (sweat-to-thread, solvent-to-thread); a bushing keeps the joining method, changes only the size.