I have a wife and 5 kids. Three of them are teenage girls, which means I hardly ever get a chance to shower. I wanted to put in a second bathroom to help fix this. I spoke with some local plumbers and they said that I should just cut the 1/2 copper after the meter and replace with 3/4 pex. They said it would give much more flow so I wouldn't have to worry about water pressure dropping if both showers were being used at the same time. The meter is 5/8 coming in and then 1/2 after the meter.
The problem for me is that I used a pressure gauge and it said that my water pressure was 84 psi. My research on the project seemed to indicate that the plumber was wrong. Increasing the 1/2 copper to 3/4 pex would increase pressure and it is already too high.
Unfortunately, I already purchased all the supplies to convert everything over to 3/4 pex. I seem to be fixated on this project. Having a hard time thinking about anything else but don't know what to do.
I fear that 1/2 copper will not provide enough flow to cover two showers at the same time. I don't think 3/4 pex with a pressure reducing valve would help as it would just reduce the flow to less than what I have now. I can't see that having the city put in a 3/4 meter would help if pressure is too high with 1/2.
How can I make sure that I can feed two showers at the same time?
I also need to install whole house water filters. Everyone complains about the water but they say anything over 75 psi should have pressure reducing valve installed. It seems to me that if I need to bring the pressure down to 75psi it would not matter if I did that with 1/2 copper or 3/4 pex as the amount wouldn't change after the reducing valve. Is this correct?
Would a 3/4 pex line with reducer to 75 psi provide any more water than 1/2 copper reduced to 75 psi? I would think that the amount of water would be the same as the flow is reduced to lower pressure either way.
UPDATE
Thank you everyone for your thoughts and advice. Honestly, I'm still a little confused as I don't know if a 3/4 pex with pressure reducer to 75 PSI will offer any more water than a 1/2 copper line with pressure reducer to 75. My thinking is that regardless of pipe size, once it is reduced to 75 psi, the same amount of water will be available. I think you guys are saying that for some reason it will so I will book some time off next week and replace all the 1/2 copper with pex. I will do a homerun with 3/4 pex coming off the 1/2 pipe at the meter. Than branch off with 1/2 or 3/8 pex to all the faucets.
If I am wrong, please correct me. Otherwise, thank you everyone for your help.
Best Answer
Bad idea. Enlarging hot water lines will dramatically increase the inventory of water sitting in those lines. I.e. How much water is in the lines themselves.
I.e. How much cold water those hot water lines are full of, when you first turn on the shower.
I.e. How long you must wait for the cold water to be pushed through and become hot.
You reduce droops by not allowing any one appliance to suck up all the water, and you do that with flow restrictions. The single best thing you can do to ease water droop is fit low-flow showerheads. Of course, if it's a shower only, with no tub diverter, that means waiting even longer for initial hot water.
Here's how I'd fix that. So I would couple that with minimizing the size of the water pipes, and have a homerun for each shower, for both hot and cold lines. And tap both right at the top of the water heater. That will ease pressure droops, and pressure droops will affect both hot and cold equally, so no chilly/scalding surges.
So for instance a 3/8" run just for each shower. A 3/8" pipe has 1/4 the inventory of a 3/4" pipe, so it warms up 4 times faster. Such a small pipe would make sense given your high water pressure and a low-flow head.