Mold?
Hello.
Bought a new construction house about a year ago, and I just found this on the underside of our bathroom sink countertop. It looks to be mold, and it is very ugly.
I think it’s Granite as the blue paper in the photo says. The blue paper is also moldy and it looks like at some point it got wet too.
What’s strange is that, including the blue paper, it’s all dry to the touch and I don’t see anything from the drain line or supply line leaking. What could be the cause of this? Everything else (cabinets, walls, etc) in the bathroom is fine. I don’t know why this countertop could be moldy like this.
The upstairs bathroom has the same countertop, just a little smaller, and it also has mold on it too, just not as bad as this one.
What could be the culprit? And how should I clean it?
Additional Photo: https://imgur.com/a/gK6Bz15