I'm about to finish the rough plumbing in my shower, wife wants 2 shower heads. I'm fine with it, but what are the specs for the pipe size? Can I buy 2 shower valves with 1/2" inlets or do I need 3/4"? I am running 3/4" PEX to the first valve and plan to reduce to 1/2" at the valve. But I can do whatever is needed to keep good water pressure, including soldering copper at the valve.

  • 2
    How do you plan to supply hot water to this? Also do you want lo-flo or high-flow? It seems like hi-flo + 2 showerheads will result in short showers before tank depletion. Also, running 3/4 pipe means waiting twice as long for hot water to come. Mar 8, 2019 at 16:58
  • @Harper Agreed 3/4 means more cold to eliminate before hot arrives. And you need to consider storage volume for a tank and max gpm for a tankless.
    – Joe Fala
    Mar 8, 2019 at 17:11
  • I just added two 3/4" tee ball valves right at my water heater (hot and cold) which are right outside the bathroom. Then 3/4" PEX into the room, maybe a 20' run.
    – BigLake
    Mar 8, 2019 at 17:15
  • Well, if the water heater is close, that helps a lot...but tank exhaustion is still an issue... With a tankless it,s an extra hard problem because it means the tankless must be big enough or it will run tepid... Mar 8, 2019 at 17:36

1 Answer 1


* you're going to want to make sure to balance flow*

In order to do that you will want to loop the pipes around back to itself.

enter image description here enter image description here

If you want to make the primary loop out of three-quarter inch pipe it certainly wouldn't hurt but is probably not necessary unless you have extremely high flow shower heads.


Here's a better image enter image description here You can use one or both of the optional valves you can even go with none but then you will always have flow through both shower heads.

Sorry I tried rotating the image it keeps going upside down

This is an example of the optional valve[enter image description here][4)] https://www.google.com/url?sa=i&source=web&cd=&ved=2ahUKEwiOycnFsPPgAhWFw4MKHSSuDd4QjB16BAgBEAM&url=https%3A%2F%2Fwww.qssupplies.co.uk%2FTaps%2FStop-Valve%2FProduct%2F485.htm&psig=AOvVaw0yBhytq_2amzj_lDQGskPk&ust=1552163162650315

  • Ok I've seen something similar to what you're saying, what is the legend in your drawing? I'd be happy if I can just loop 1/2" that would be easy. Thanks for the responses.
    – BigLake
    Mar 8, 2019 at 17:11
  • Is that loop only hot water?
    – BigLake
    Mar 8, 2019 at 17:12
  • 1
    Adding a better picture...
    – Joe Fala
    Mar 8, 2019 at 17:21
  • 1
    Yes it's the mixing valve, and without any of the "optional" valves both shower heads will run every time.
    – Joe Fala
    Mar 8, 2019 at 20:20
  • 1
    Added a photo with the valve, it was hard to find online, I searched wall mount shower valve. Bath supply company's stock or order them to match your other hardware.
    – Joe Fala
    Mar 8, 2019 at 20:31

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