It seems to dry pretty quickly, in my experience from the couple times it got wet. Here is what the BedRug folks say on their website in the product description:How fast does the BedRug dry after getting wet or rained on and does moisture soak through to the underside?
I have a cover but often toss wet kayaks in there or wet scuba gear.
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The BedRug material is fade and UV resistant. Made of foam similar to that used in life jackets, it doesn't absorb water and will not mold or mildew. Water will simply run off the surface, through the zippered perimeter, out the factory drain holes in the truck bed and will dry in as little as 20 minutes. Just clean it with a hose, power washer or vacuum and your BedRug is good as new.