If we could waterproof our kids, we would. A nice coat of sealant, and then just hose 'em off once a day. But seeing as this isn't feasible (or safe, or legal), the Tady Tote's the next best thing. And once it gets dirty, you can just throw the whole thing in the washer (the tote, not the kid).
Tady Tote inventor Sharon Soloway was stepping into the bath one day when she suddenly realized that the amount of water displaced had to equal the volume of her submerged feet. Crying "eureka!" she jumped out of the bath and promptly designed the Tady Tote, which didn't have anything to do with volume displacement, but was a good idea nevertheless. King Hiero II was quite pleased.
Tady Tote official site