Plumbing Fittings

Plumbing fittings are the connectors that join pipe segments together, change direction, split flow, change pipe size, or terminate a run. Every joint in a plumbing system uses a fitting — a typical 2-bathroom home has hundreds of them.

What are the common types of plumbing fittings?

• Coupling — joins two pipes of the same diameter end-to-end
• Elbow (90° or 45°) — changes pipe direction; 90° elbows are the most common
• Tee — splits one pipe into two (or joins two runs into one); used at every branch point
• Reducer / bushing — connects pipes of different diameters
• Cap / plug — terminates a pipe end; used during rough-in and for capping unused ports
• Union — allows a pipe segment to be disconnected without cutting; used near appliances for serviceability
• Wye (Y-fitting) — branches at 45° rather than 90°; preferred in DWV systems to maintain drainage slope

Do fittings need to match the pipe material?

• PEX pipes use crimp, clamp, or expansion fittings (brass or poly)
• PVC and ABS use solvent-weld fittings in matching material
• Copper uses sweat-soldered (95/5 solder) fittings or push-fit connectors
• Galvanized and black iron use threaded fittings with pipe dope or PTFE tape

Dielectric fittings are a special case — used where copper and galvanized steel meet to prevent galvanic corrosion (electrolytic reaction between dissimilar metals). Dielectric unions or dielectric nipples contain a plastic isolator that breaks the electrical connection between metals.

Push-fit fittings (like SharkBite) are designed to connect pipes made of different materials without soldering or crimping — the fitting grips the pipe with internal teeth and an O-ring seal. They're popular for repairs and remodels where speed matters.