Wet carpet near basebord, out side of bathroom? What could this be?

We have been noticing our carpet near the bathroom about a foot away from the entrance has been wet along the baseboard and is starting to smell like mildew? We live on a slab.. We think it could be coming from the toilet pipes but were not sure. The bathroom itself does not feel damp or wet only the carpet outside and the the right about a foot down feels wet.