How to Plumb a PEX Water Supply System

PEX pipes.
  • 3-4 hours
  • Intermediate
  • 150-500
What You'll Need
PEX pipes
Fitted manifolds
Wooden rail
Valve fittings

After you secure the manifolds to the pipe supply systems and add supply lines and fit the manifolds to the framing units, you will need to take your PEX plumbing from the fixtures you are using to the manifold, adding a nail plate to protect it. You will also need to connect PEX pipes to the shut off valves on the manifolds, and then plug up the unused valve outlets on each manifold. Plumbing in a PEX unit should not be too difficult, and can usually be managed in a few spare hours.

Step 1 - Taking the PEX Fitting to the Manifold

Where you have placed the manifold might not be too convenient for you to take the PEX pipe. One solution to this is to take the piping behind the walls. Remove a small area of piping from both ends, and slide the pipe between the two. You will also need to add a nail protector between the pipe and any studs on the walls. This is a simple addition and involves a metal or wood rail which is placed along the bottom of the wall, just in front of the pipe. You can use the metal lids off of old boxes or connection plates if you wish. Secure the rail by nailing it to the bottom of the stud, and then you can push the pipe up towards the manifold.

Step 2 - Adding the PEX to the Manifold

You can not connect the PEX directly to your main water supply line, so the manifold is one way of allowing you to connect the two different types of water pipe. You should take the PEX to the manifold, and attach the pipe to the hole in the valve. Using the bolt in the valve connection, you will then be able to tighten the nut until the pipes are held securely in place. The valve should be connected to the shut-off connections on each manifold so that if necessary you will be able to shut off the water without affecting the other parts of the bathroom or utility room.

Step 3 - Plug up the Manifold

Once you have finished installing your manifold, you will then have to plug up the excess valves in order to prevent water from flowing out of them. Fit some short pieces of the PEX piping into the valves. You will be able to connect two excess valves together by putting each end of the short pipe into position. Once you have done this, you can then tighten the valves on the manifold until the PEX pipes are held securely in the valves. This will protect your water supply system and keep it running effectively.