My husband and I are NOT handy and must hire people to help with home matters. I'll try to explain my question as clearly as possible.

The house is a one story ranch. The basement is unfinished. We can see the vent stack going up from the elbow straight through to the roof. During a heavy driving rainstorm the other morning we had water dripping down the pipe and onto the floor. The water was clear/clean.

We called our plumber. He looked at the pipe from the basement and concluded that it was probably a roofer problem. He concluded that the seal around the pipe was probably faulty. He did not go into the attic or on the roof.

We called a roofer. He went on the roof and said that the seal is secure around the vent stack. He said he thought there was a possibility that there was a crack in the pipe or there was some other internal sealing problem. He suggested that we buy a rain cap for the stack rather than spending money having the plumber search for the leak.

We also have a tiny bit of old water damage on the ceiling in the bathrooms that probably are on each side of this pipe. We had a handyman go up in the attic and he told us that it was from condensation from the exhaust fans in the bathrooms. Now I'm thinking that wasn't right since the water spots are back to back and I think the vent stack is in between.

I've researched everywhere and don't find a rain shield for the vent stack which tells me it's not a very good idea. I've put a call back in to the plumber but I'm concerned that we are getting the run around. We want to be informed homeowners. Most of all we know it's not good for water to be entering inside our walls.

Is it possible for the vent stack to leak into the house? I know the top is open because any rainwater that went into the pipe would go into the sewer system. So if the roof is secure then how could water be getting in?

Your help would be appreciated.

While anything's possible a roof vent leak is more likely to be found at the vents roof flashing rather then a split in the pipe or a leaky joint. What material's the pipe anyhow?
Unless the roofer took a hose up on the roof and loaded the area around the vent flashing with water, with someone in the attic to look for moisture, it hasn't been checked. Just looking at it and saying it's OK doesn't get it. They do make vent caps, (see image) but my bet's still on the flashing.
I guess if the attic were hot enough and the vent stack was cold enough the exhaust fan could exhaust enough moisture laden air for it to develop condensate, but it's a stretch. Good luck, Tom

The pipe is PVC.

The roofer just looked at the flashing. He didn't use a hose. He said the plumber would do that.

Sigh. We are caught in the middle. I guess we could try another roofer.

It is very unlikely that the pvc pipe is leaking, even if it had a crack I doubt much water would make it through, it should be easily detected by going into the attic and looking for the problem area. I'm almost posative it's in the flashing. A quick fix would be to buy a gallon of tar and give the flasing a really good coat

It ended up being a leaking vent stack. It was not a roof issue. Oddly enough, it was my roofer who finally diagnosed the issue. The plumber would not go on the roof and do the water test so the roofer did. There was a joint in the vent stack that the roofer notice had been done poorly. He put water inside the pipe above the joint and we could see water in the basement AND in the attic. When he put the hose in down past the joint... no water. The roofer is a sheet metal man and said he could fix the problem. We let him since our plumber had been out to the house twice, had been in the attic and looked at the pipe, and didn't find anything wrong.

So far, so good. I just wanted to let folks know that it ended up being a plumbing problem after all.