Hello, How much can a large cat pee at one time? When Rusty goes the clump of litter is about 3 or 4 times the size of when Angel or Missy go. When I clean the boxes some of the clumps after Rusty goes are the size of a baseball. Is this normal for a big cat? I am guessing he weighs about 16 or 17 lbs now. Panther is real big also but I never can catch him in the box to see if he also pees out so much. Panther and Rusty both have the same mom cat but Panther was from a earlier bunch of kittens than Rusty.