We noticed a ceiling stain below our attic, so we looked in our attic and saw the pvc pipe coming straight down from the roof then it runs horizontally with the ceiling and then it is cut-off. Just below where it is cut is where the stain is at. Is it normal for the pipe to be cut? Is it normal for water to come through the pipe from the roof? Doesn't seem right. I noticed another horizontal pvc pipe that is cut also. Too much insulation to see where it is coming from.

There are vents that go through roof that connect to drain system, sounds like it is disabled right now. They MAY need to connect together and go out the roof pipe.

Ir's probably a vent pipe that never got connected, perhaps for a bathroom vent. It is supposed to go somewhere, or if they used another vent, it should have been removed. At any rate, it's not correct as is. You need to determine if indeed it is to be either hooked up or eliminated. If it's not needed you may just be able to cap it off on the roof, rather than removing it and incurring roof repairs.

If its not needed, they make a plastic Weatherhead that could go on old roof vent pipe. Would allow FM, Marine, Satellite Antenna wires.

What type of company/contractor would look at this? Plumbing, roofing, etc.

Plumber.

This sounds like someone has deliberately disconnected the drive-up bank transaction tube from your house. Reconnect ASAP, you are losing money every day this situation exists! :D

The 2 pipes that are cut are somewhat close to each other - a foot or so apart. What is a drive-up bank transaction tube? How should they be connected? How are we losing money? Thanks.

Mng... KC13 is TRYING to be funny... emphasis on trying. But it's up to a plumber to figure out what has been done, or in this case not done.
Good luck.

The 2 pipes that are cut are somewhat close to each other - a foot or so apart. What is a drive-up bank transaction tube? How should they be connected? How are we losing money? Thanks.Sorry, I didn't think you would take that seriously for even a second... you know... the vacuum tubes used at banks?