Is it possible to place plumbing on an external home wall?

[Matthead012]

Pipes can freeze everywhere, especially in Buffalo, NY, during our cold and unpredictable winters. Sometimes the only place for plumbing to go is via an exterior wall. While there is a plumbing code particular to where you live, and your local experienced plumbers will be familiar with it, you may find or need to install plumbing in an external wall. This may have you thinking if plumbing can and should be installed in an exterior wall.
A water line on a cool external wall is almost always a recipe for disaster. It probably doesn't matter how well the pipe is insulated; it will freeze on the coldest days. Unfortunately, when installing plumbing, an exterior wall is frequently the only option, especially in older homes. Pipes should not be installed in unconditioned attics in colder areas, such as Buffalo.
It is best to avoid installing water-related plumbing in outside walls or unheated attics. Plumbing fixtures should be installed on the inner walls. If the plumbing is on the outside of the house, the pipes should be well insulated. To further protect the pipes from heat loss, caulk or foam all seams between the back wall of the cavity and the framing, and cover any holes through the framework for the piping. In addition, cavity insulation should be put behind the pipes and between the pipes and the outer wall. Anything that can be done to keep the pipes warm and prevent them from freezing, should be done.

[Gormicsta]

 Yes, it is possible to place plumbing on an external home wall, but there are some things to consider, like insulation, vapor barrier, and freezing temperatures. So whatever thing we are doing, we should also consider the side effects.