Is there a certain pressure that should be used when using air or water to test for leaks? I'm hoping to use water as I already have the fittings to hook the exhaust up to a garden hose. Just worried about putting too much pressure in them. Thanks

If you use a garden hose, it wont be too much pressure. If that were to "cause" a leak, they were going to fail soon anyway.... IMHO

I concur . Turn on the hose and let em set for awhile . Welded stainless steel should be able to take much more pressure than is in your home's waterline .

A garden hose is a pretty severe test. You only need around 20 psi.

I figured it should survive a garden hose but didn't want to tempt fate by putting in so much more pressure than it would see during use.