PEX--Home Runs or Branching Off


Old 03-03-11, 07:33 AM
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PEX--Home Runs or Branching Off

I'm planning on redoing one of the bathrooms upstairs in our two story home. There are two bathrooms that back up to each other with a common 2x6 plumbing wall.

I was considering replacing the copper supply lines with PEX as the copper is approaching 30 years of age and I have water that is acidic and hasn't been treated for years since the treatment system went toes up.

Right now the copper to the upstairs is a 3/4 main for hot and cold and branches off to feed the fixtures via 1/2" lines. I'm feeding six colds for the two toilets, two sinks and two showers and four hots for the two sinks and two showers.

Should I use 1/2" home runs for the PEX and feed each supply individually or just run a 3/4 hot and 3/4 cold and branch off to each fixture with a 3/4x1/2x3/4 "T"? Water pressure right now is okay, but not great. Certainly can't run two fixtures at one time and get adequate flow. I'm on a well/pressure tank system.

Running ten 1/2" Pex lines may be difficult due to the way the current copper is routed through the walls and above the ceiling in the kitchen which is under the upstairs bathrooms. Either way, I'm in for some drywall removal and reinstallation.
Old 03-03-11, 08:26 AM
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I would just run 3/4 and branch off. The issue may be the main line from the well. When I moved in my well was pipped 3/4 and 1/2 everywhere. No volume. I cut everything out and ran a 1" trunk line and branched off of that. I get 65 psi on a shallow jet well. Shower and flush a toilet make no difference.

Just my opinion.

Mike NJ

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