pex tubing size for shower

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Dan82564

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does 1/2" pex supply enough water for a shower? Can I supply the mixing valve with 1/2" and use 3/4" pex for the line from the mixing valve to the shower head?
 

Dan82564

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Just use 1/2” for all of it.
Would 3/4 give me more flow? I have the fittings for 1/2 inlets and 3/4 out to head. If it will hurt more than help I can get another fitting for 1/2". I dont really understand flow vs. pressure.
 

Twowaxhack

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The flow is usually limited by the rough valve and or the shower head.

You doing something special ? High volume heads eat up a lot of hot water quick. What’s your water heater situation ?

What’s your starting water pressure ?
 

Dan82564

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He is planning on getting a shower head with the attached shower arm. Gas water heater 40gallon. I dont know where or how to get the water pressure. Its public water. If we were to leave the 3/4 in going to the head could it have a negative impact
 

Twowaxhack

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He is planning on getting a shower head with the attached shower arm. Gas water heater 40gallon. I dont know where or how to get the water pressure. Its public water. If we were to leave the 3/4 in going to the head could it have a negative impact
It’ll work.
 

Dan82564

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It’ll work.
by "it will work" did you mean the 3/4 will work? We plan on closing up hte wall this weekend so if I need to switch it to 1/2 I'll need to get that done first.
Thanks again
 

Twowaxhack

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by "it will work" did you mean the 3/4 will work? We plan on closing up hte wall this weekend so if I need to switch it to 1/2 I'll need to get that done first.
Thanks again
Yes, 3/4” pipe will work. But you’ll most likely need to reduce it back to 1/2” for the shower arm.
 

FishScreener

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Typically showers are done with 1/2-inch piping. Most shower heads in the US and Canada are limited to 2-gpm by code. So the 1/2-inch in PEX is more than adequate. In some jurisdictions they are mandating 3/8-inch PEX for the hot feed to decrease the amount of water needed to get the hot water to the shower from the water heater.
 

Zanne

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You'll have to reduce to 1/2" for the showerhead so using 1/2" will work. If you have a mixing valve that has the waterlines come from below or above and they have to make 90° bend, instead of using the fittings that make them bend, if you have enough space you can get 3/4" gray conduit elbows and slide the PEX through them to make the bends. My friend did that with his shower so it took fewer fittings and didn't restrict flow as much.
 

hdtvkeith

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does 1/2" pex supply enough water for a shower? Can I supply the mixing valve with 1/2" and use 3/4" pex for the line from the mixing valve to the shower head?

I just redid my entre plumbing from copper to Pex-A. 1/2 is fine. I ran 3/4 inch main everywhere then 1/2 branches to fixtures. One thing I noticed is if you leverage bends vs. 90 elbows as much as possible the flow/pressure is great. When my house was built they had 90 elbows everywhere, the pipes ran in such a inefficient way I found the furthest points always seemed less than the points in front of all the elbows. We used to keep the house at 72psi and now at 62psi I feel like I have better flow and pressure than before. As @Zanne said, use bends wherever possible to reduce restrictions on water flow.

This is master shower, I ran 3/4 then branched down to 1/2 split for shower and toilet in the adjoining bathroom. The cover pipe is the hot and that is 1/2 from the last split under the floor

1659607567938.png




Not a pretty job, but here is my journey t re-pipe my home.

 

Twowaxhack

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I like making slow bends. Much longer radius than the manufacturer says is acceptable.

Or I’ll use a 90.

If the water pressure at the house is above 60 psi there’s no problem using 90’s unless you go crazy using them.

I find a lot of failed pex where the tubing bends. That’s where it fails first. If you have problems it will be in those bends.

The crimp style pex fittings that restrict flow more are not a problem when you have excellent pressure. The idea was that the pipe is flexible and you’d use less fittings to install it to help make up for the smaller ID.

Also everything is low flow except tub fillers and custom showers so it doesn’t matter.

So again, if you have 60 + psi it’s hard to screw it up.
 
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