3/4" copper main line to Pex-A?

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Soupy

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I'll be keeping with the branch system. I have 3/4" copper coming into my house. The rest of the pipe is Galvanised what looks to be 1/2" to me. The diameter is roughly 7/8" OD. I want to replace all that. I'm adding a 2 cuft water softener. Should I go 1" PEX A from the 3/4 copper to the softener and HW tank, or will 3/4" be enough? My main concern is the softener.

Also going from the HW heater to the Kitchen. That section has already been replaced with 3/4 cpvc. It takes forever for hot water to arrive. Would 1/2" PEX-A be enough to split off to sink and dishwasher for hot water line. Or should I leave that section as is for now. It's about 20 years old. I'm guessing it's about a 50ft run.

Thanks
 

Reach4

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One inch PEX would be better until you split the plumbing into hot and cold paths. 3/4 inch copper is bigger ID than 3/4 PEX, which is 0.681 inches. 3/4 type L copper is .785 inches ID, and type K is 0.745 inches.

For a bathroom, you would commonly run 3/4 inch PEX for cold, and 1/2 for hot.
 

Soupy

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One inch PEX would be better until you split the plumbing into hot and cold paths. 3/4 inch copper is bigger ID than 3/4 PEX, which is 0.681 inches. 3/4 type L copper is .785 inches ID, and type K is 0.745 inches.

For a bathroom, you would commonly run 3/4 inch PEX for cold, and 1/2 for hot.
So 1 in to the softener that to the HW heater. From there 3/4 branched to 1/2 stub outs for fixtures. On the Hot side is Half inch fine as the branch and stub out. I have 2 baths one just a shower but we never really use that one. The kitchen is one line up to the sink then a two way to sink and dishwasher. The master bath has the sink and bathtub/shower. Is 1/2 inch enough for all hot water lines? No one uses the BR sink while in the shower.
 

Reach4

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You could go 1 inch or 3/4 to the WH, but now that you mention it, running 1 inch to the WH makes more sense. I am not a plumber.

On the hot, perhaps the bigger thing is that 3/4 slows the arrival of hot. If you are using 2.5 gpm showerhead, and 1.5 at the lav at the same time, 1/2 inch pex could handle that fine, for the occasional sharing. And often those are not using 100% hot.

The cold is also supplying the toilet.
 

Jeff H Young

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A factor is whether the bath room has a tub or tub / shower vs a shower only 2.5 gal max bath tubs have higher fixture count . many people often say shower when they mean a tub shower so if you choose 1/2 inch you might take that into concideration
 

Soupy

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A factor is whether the bath room has a tub or tub / shower vs a shower only 2.5 gal max bath tubs have higher fixture count . many people often say shower when they mean a tub shower so if you choose 1/2 inch you might take that into concideration
Yes the master bath has a large tub and a shower with a moen dual showerhead attached. I am perfectly fine with my current water pressure and volume. I did have to remove the shower head restrictor though. The tub and shower have 1/2 copper down to the crawl space. transitioned into the old galvanized pipe. We had a new tub and shower installed a few years ago.
 

Jeff H Young

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commonly a 3/4 would be running to a master with a seperate large tub and double head shower and of cource either 1 or 2 lavs. Ill say 1/2 inch is undersize and stand by that but if it works for you no argument from me but its a sub standard installation.
 

Soupy

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commonly a 3/4 would be running to a master with a seperate large tub and double head shower and of cource either 1 or 2 lavs. Ill say 1/2 inch is undersize and stand by that but if it works for you no argument from me but its a sub standard installation.
The washing machine picks up off that branch too so I'll run 3/4 hot to the Master Bath.
 
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