HOMEFLASH

First of all, I do not understand why bathroom showers are designed NOT to have separate water line to be shut off and turn on.

Second, for changing shower facuset or cartridge (moen), I know I must turn off main water valve.. (correct?).. My concern is ...

What if there is something wrong during the installation, inproper insert, etc. So, as soon as I turn back on the Main water line, water may come splashing. Because of that, the whole house will be out of water. Of course, that is my speculation, I really want to know if there is a way to ensure

that the rest of the house still have water supply even if that replacement failed.

kok328

I don't understand why either but, that's just the way it is.
If something goes wrong with the installation, then yes, you will be without water in the entire house until you can make the repairs.
The only thing you can do is install shut off valves on the shower your working on so that the water can be turned back on without having the shower.
However, I suspect there is some type of code regarding the shut off valves on showers that we're not aware of.

HOMEFLASH

I just spotted some interesting words here.. shut off valve?

How do I install shut off valve? what does it look like, does it sound more complicated on top of the regular installation?
the shut off valve is to the shower, not to the regular/cartridge (inside the hole) part, correct? If so, that is useless because that is where the problem may be.

Redwood

Individual shut off valves for tubs & showers are not required under most codes I know of.

if fact under most codes I know of, concealing a valve in the wall would be a violation.

You can install valves with a means of access or, in a basement or, crawlspace. Also some tub/shower mixers are available with integral stop valves.

kok328

The best case scenario I was thinking of was to install a simple ball or gate valve somewhere in the basement where it can be readily accessed.
The worst case scenario would be having to install one in a crawspace just for the obvious reason of a less desirable location.
However, Redwood has identified a pretty sweet option.