Mysterious Drop Ceiling Water Stain

Got a finished basement and the the wife noticed a water stain on the ceiling tile right below the gas intake pipe. There are some water line pipes near the area but nothing directly above the spot and no visible moisture now, as you can see from the pics. Still, I'm a bit worried.

The kitchen sink is above this area but like I said, no visible moisture now. We have had a lot of rain recently. Don't know if that could mean a vent pipe issue. Any ideas?

This is the type of question that is A LOT easier to answer if you're standing there looking at the problem, but I would tell you to check around the top of the wall if you can up between the joist spaces just to check for any other water staining. This may give you a further clue as to where it's coming from.

The rain getting in around the vent pipe is a good possibility. Go up on the roof and inspect the vent pipe flashings to check for a good seal. Take some silicone up with you

Thanks. It's really hard to see anything because of the wall framing but I can't see any water stains on the joists or on the subfloor as far as I can tell. It's almost like one of the pipes was sweating. But it looks like too much water for that. Also checked under the kitchen sink for any moisture. Nothing.

I hate to get up on my roof since it's really steep but it sounds like I may have to do that. Is there typically one vent pipe at the top or multiple? This water stain is at the far west side of the house. Is it typical for a leak to make it's way all the way to the basement, to one far side of the house?

Edit: How about this possibility? Since we had really hard rains in the last week, might I have an issue with the spot where the gas pipe enters the house? Could water have entered the house there and followed the pipe to the spot? It's about 15 feet away. I can caulk around the spot and see what happens. Just wondering if this is even possible. Can water follow a pipe that far before dripping down?

yes it can and very often do or even further !

So your leak could be coming from 15' or 30 ' away till it gets to a point it will drip down on !

Well, I'm 99% sure it was the gas pipe. The putty around the pipe/siding moved and water could have gotten in that way. For now I remolded the putty around it. I'll get some new stuff later.

Man, it's one thing after another when you own a house...