I use the World's Best and yet my cats prefer the cheap clumping litter. I am hoping to stop buying it soon, and just use W.B. I do not flush it. I can't imagine what it would do with and to a septic system and it seems to me it should be going in the ground fills and not the water system, but that's my opinion! It is made of corn and it clumps too - great combo. I am not wild about the aroma but it isn't bad. Like I said, my cats use it but prefer the other for some reason. Maybe just habit.

Its not easy to find World's Best. There is only one store in the Burlington VT area that carries it. Its a tad expensive but goes a long way.