When one of my lw rugs was starting to leak in heavy/persistant rain last year I washed with nikwax and then used a spray-on reproofer as well. Seems to have done the trick.
Lol I never clean mine - pointless as the minute he gets out he rolls LOL!
What spray on did you use? Rug in question is a rain sheet. Also if you do it in the washing machine can you still put the rug in a duvet cover to protect the machine?
I bought some fabsil in a tin and painted it on mine, but I think the spray is just as good. I don't like the can-type-sprayers but they do them now more like the fly spray type and they're better. You will need to wash the rug first though. Personally I don't like the wash-in stuff (which is what they'll use if you send it off).