Shower remodel-3/4" or 1/2" copper?

[walker lutz]

Hi I am in the process of remodeling my shower and have already received some great advice on here figuring out my drain situation.

I am planning on installing a shower wand as well as a rain head and will have a separate thermostatic valve for each so I have the option of running them both at the same time. The bathroom in on the second floor and has a 3/4 in line supplying the bathroom, it then t's off to supply the bathtub lav, and toilet.

My question is: would it be worth running 3/4" the extra 8 feet to the shower or should I just tie into the 1/2" bathtub supply line (which would only be a 3' run of 1/2"? I haven't tested my pressure yet but it seems good. I filled up a bucket in the tub and figured that I am getting about 12 gpm of flow. Would the 3/4 vs the 1/2" make a noticeable difference in the pressure?

 

[Flapper]

The showers are limited to only 2.5GPM or less, right? So at most you'd be using 5 GPM. If so then 1/2 should be ideal.

 

[Sponsor]

 

[Jadnashua]

I don't see the allure of a rain head...since it's still limited in the volume by Federal regulations, spreading that limited water out across a large area means you can't rinse off anywhere as easily as with a 'normal' head.

As said, though, for a single showerhead, 1/2" pipe is fine. If you were worried, you could run two separate taps off of the 3/4" line, rather than splitting the 1/2" line, run two 1/2" lines from the 3/4", but it should not be necessary. The copper tubing organization recommends not designing anything for more than 5fps of flow for hot water, and that's 4gpm in 1/2" copper. Throw in, you normally don't run 100% hot, and you should have plenty for two heads off of one 1/2" line, but in case you decide you want to add another head or body sprays, more doesn't hurt. A larger pipe will take longer to flush once it cools off.

 

[Cool Blue Harley]

Do not tie into the 1/2 inch bath tub waterline. That 1/2 inch pipe is already maxed out serving a bathtub which is rated at 4 water fixture units, due to its unrestricted spout. Run 1/2 inch to your shower from the 3/4 inch pipe. Your shower is rated at 2 water fixture units per head.

 

[walker lutz]

Great! Thanks for the advice!