We need to test a gas copper line for leaks and we're currently using
water at about 115 psi and a pressure gauge, but I am not sure this is
the right approach.

I'd like to ask what is the standard procedure to test a gas copper
line for leaks.

Is water or air used?

At what pressure?

For how long?

What would be an acceptable drop in pressure in this period of time?

Can an unexpensive pressure gauge ($15 or so) be used with water or
air?


Thanks a lot in advance.