Heck, I wish you were my son-in-law, at least you are trying to fix things. Snake and rod are the same animal and both have more force than a garden hose. The hose may help and if the water builds back up to the roof in the stack you got your answer. Lets go with Tom because he's got so darn much experience I want to learn his tricks too. Get you bucket(s) ready and follow Tom's directions, I'd even get two buckets ready just for the fun of it.