Can I run 1/2" pipe from 2/1" pipe?

Question

I am pulling out hot and cold water line in my basement. New copper pipe will be 1/2". I have choise to connet them with existing 1/2" line, or existing 3/4" line.

Connecting to 3/4" pipe is kind of little difficult, so I want to cut existing 1/2" copper pipe, put a T joint on it, and connet new 1/2" copper pipe.

Is it ok to run 1/2" line ffrom existing 1/2" copper pipe? or it should be conneted to bigger size of pipe?

This location is is in ILLINOIS, USA

Answer 1

Your question is worded in a way that I cannot follow; the State of Illinois has its own Plumbing Code (much stricter than say, the International Plumbing Code). I suggest you contact your local Plumbing Inspector and ask him, maybe even give him a diagram. Most places in Illinois do not require a permit to install a replacement water heater, unless you are changing from one energy source to another; but the Inspector may even come out to take a look, anyway (if you ask nicely).

Remember, the water lines are installed based on the volumes of the fixtures they supply. Don't expect to get the same pressure or water volume if you start changing pipe sizes. (If you live in the People's Republic of Chicago, you are not allowed by Prince Richie to do ANY plumbing or electrical work, even in your own home; think about that when casting your next ballot.)

Answer 2

It should be just fine as long as you are not trying to run your whole house through half inch lines. If this will be the main supply line for either hot or cold it should be run with the larger three quarter lines to allow for better flow if you have a couple things running. Hope this helps.

Answer 3

you should run your main line at 3/4 and off the main run 1/2 to each fixture