Or do what I do....find where the hose exits underneath the floor on the passenger side. Once you find it, you'll remember it for next time. It's a fairly large diameter so I happened to have a length of rubber hose that fit snuggly inside the drain hose. Then I just blow into it by mouth. I suppose some cars might need an air compressor, but mine never did.I did this the other day on a friend's 2007 when she had water dripping on the driver's side. In the interest of hopefully saving someone some stress on their back I believe you'll find it much easier to kneel on a pad outside the passenger door opening and access the hose that way instead of contorting yourself on your back. I'd never even looked at the car before and was in and out in maybe 10 minutes after clearing the spigot the hose attaches to, the hose itself was fine.
I now just make this a routine job in the late spring, after all the tree stuff etc is done falling.