Stagnant water smell

help, after driving my 2008 volvo S80 for about 15 minutes and parking it in my garage there is a stagnant water smell around the car. we bought the car 3 weeks ago and the smell just started last monday. smells like a damp basement. smell is strongest outside the car near passenger doors/rear wheel

I love to leap to conclusions, here is mine, you have a leaking sunroof that allows water to pool where it should not, and when things get warm you smell it more. I would love to be wrong in hearing you do not have a sun/moon roof.

Hope it was not in a flood at some point in the past.