For a bathroom pex plumbing should I go with trunk-branch or with a home run manifold plumbing layout?

Question

Below is the layout of my bathroom and my starting point are the red/blue vertical copper pipes you see in the picture. The walls you see will be tiled so not sure how much sense would make to have a manifold somewhere.
I will need box behind the shower panel. I am considering running the trunk and lines low near the ground and the dry vent and the drains (green and yellow pipes) at the level of the inflexion point of the shower. I would like to install them up near the ceiling but I don't think that I have enough room behind the two vertical copper pipes (red and blue) to the right of the shower

Fresh Codemonger · Answer

I home run cold tap water lines 1/2" as close to supply as possible so I can get cold water ground temperature for drinking with the shortest wait possible - assumes your tap water is good quality.  Not sure if you'll be drinking the cold water from the bathroom.
I home run hot water lines as close to the hot water tank as possible so again I wait the minimum amount of time to get the water at the tank temperature.
If I was only re-doing this bathroom I might do the last mile here as if it was homerun plumbing up to your take off point and if/when you redo the rest you could update it.

Old Uncle Ho · Answer

My understanding is that manifolds must be exposed, so can't be buried in a wall, say, like behind wallboard or tile. What I read also specified that you have cutoff valves either at the manifold on each line, or accessible near each termination (point of water use,) and that placement might be determined already by your AHJ - the Code Dept or
Authority Having Jurisdiction.
SOURCE: PlasticPipe.org - check their publications

For a bathroom pex plumbing should I go with trunk-branch or with a home run manifold plumbing layout?

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