Connecting Fixtures to a PEX Residential Water System

Connecting a Kitchen Sink to PEX

These PEX lines are the standard 1/2" with blue for cold and red for hot. They are crimp type connections. The following illustration shows a PEX to compression Supply Stop. This Supply Stop serves two purposes, to tie in the existing fixture to the new PEX lines and to serve as a shutoff for service. Compression connections use the O.D. (Outside Diameter) measurement standard.

ILLUSTRATION: Straight Supply Stop 1/2" PEX to 3/8" O.D. Compression Male. The stop valve on the left picture is a traditional full flow valve while the two right side pictures show the newer quarter turn ball valve type. Quarter turn valves last longer. Traditional full flow valves can be served by replacing the internal rubber O ring. The O ring goes bad due to being compressed, especially if too much force is used twisting the valve to shut the water off. Plumbers now prefer the newer quarter turn valves as they are more reliable.

Kitchen sink faucets typically have braided metal flexible connectors that hang down as opposed to the way bathroom sink faucets connect to FIP right on the fixture. These flexible connectors have the compression style connector for you to connect to your stop valve or directly to the plumbing. Stop valves are traditionally used, but with PEX installations with a manifold and dedicated supply lines, the local stop valves are not necessary.

Connecting a Toilet to PEX

ILLUSTRATION: There are 3 parts to this toilet connection. From the top down first (1) the braided stainless steel flexible water connector with the 7/8" Ballcock on top screwed into the threaded connector on the bottom of the toilet tank, and the 3/8" Compression on the bottom connected to (2) a straight stop valve with a compression fitting on one end and 1/2" PEX on the other to (3) the 1/2" PEX cold water line secured by a crimp ring.

Connecting a Bathroom Sink to PEX

Home using a PEX manifold do not require an at fixture Supply Stop (shutoff) because fixtures can be shut off at the manifold. In this case, the bathroom sink has a dedicated supply on both the hot and cold manifolds. The water supply can be shut off to the bathroom sink at the manifolds without shutting off any other fixture. PEX is more flexible than PVC and copper. For this reason, you can run PEX directly to the fixture, without using a supply connector or supply stop.

ILLUSTRATION: 1/2" PEX to 1/2" Swivel FIP Faucet Adapter