On the bottom of the kitchen sink and all of the pipes and tubing around it there is something that looks like sawdust growing and it is spreading. It’s a 4 year old house and I contacted the builder and the plumbing contractor and they both refuse to come take a look at it, even if I pay for them to come look at it. They both tell me that they are not liable. I think they think it is mold. I have no idea what it is.
Any ideas? BTW, I have another plumbing company coming to look at it later this week.