Basement Waterproofing - Up close on the white chalky stuff

It looks a little fuzzy, doesn't it? This is probably why so many people think it is mold growing on the basement walls. Many times you can see a sort of Christmas tree pattern on a wall. That is because the concrete blocks are hollow, and when the hollow cores fill with ground water they leak out very slowly. You can see it in this picture, how the stain is from top left to bottom right, just imagine several of these blocks stacked up to make a wall. It would look a little like a tree, right?