I can't talk to that really, other than to say that the material looks like a rug, but is all plastic. It does not hold water at all. It is a really interesting material, honestly. From what I've read, trapping water is not a concern of them. I really haven't seen much in the way of negative reviews of the BedRugs, other than the material can catch things like wood chips in the fibers. Most people say if they are going to haul wood just throw down a tarp to contain most of the chips. Sounds like most anything can be removed by pressure washing it.I'm curious how the mats don't just trap moisture against the bed.