Finding the right plumbing tee is an easy job for seasoned installers, but do-it-yourselfers may have second thoughts when looking for the one they need. Any tee (for copper, PEX, etc.) is sized by the nominal size of the piping. The nominal size of copper used for plumbing and heating is the pipe’s inside diameter.
A tee with only one listed size has the same dimensions at all three of its openings. For tees that have multiple-sized slots the two sides are listed first, followed by the opening between them. The larger of the two sides will always come first. See SupplyHouse.com for a complete selection of plumbing fittings.
