I recently moved into a new home (7 years old), and there is a distinct mildew smell in the upstairs bathroom. It seems to be stronger near the toilet, which backs to a bedroom closet where I can also smell mildew. I had a contractor in my home and asked him if we needed to check inside the wall, because there is no visible mold anywhere to be seen. He said if there was mold inside the wall there would be moisture, which would leak through the floor or wall to the downstairs. There is no visible moisture on the inside or outside. Any ideas? The smell is driving me crazy. I bought "Dri-be-gone"; crystals that soak up moisture and put one in the bathroom and one bedroom closet. Each has collected about 2" of water, but the smell is still strong.