Quote Originally Posted by Wulf202 View Post
I find that often these are from a vent pipe that they forgot to glue or something simple like that
I'd go with this for $200 alex. Seen it before only on an interior area , turns out it was from the bathroom vent pipe. Old steel line not the pvc used today. The line ran onside the wall and had that same discoloration in the crawlspace.

http://www.bestmaterials.com/detail....FR6ewAodzSQDIg

http://www.flexsealproducts.com/prod...FQMtaQod8MMKNg