Waterproof mats can be used outdoors and left outdoors as well. These are usually vinyl-encased products that can’t be damaged by water. You can feel safe taking them outside, but do it only when you have to. If you need a mat for your home, it’s best that you only use it indoors. Although it might not be damaged if you take it outside, you’ll very likely shorten its lifespan. Also, you’ll need to wash it and clean it properly. If a mat that is not vinyl-encased gets in touch with water, it will absorb the liquid and become a breeding ground for bacteria, mold, and mildew. That’s not something you want to take home or have at home.