How many litter boxes does a multi-cat home need?

One per cat plus one extra, placed in different parts of the home. Cornell’s house-soiling guidance specifically flags inadequate litter box numbers and inappropriate placement as common contributors to litter box avoidance in multi-cat households.[1] The placement matters: boxes in the same room defeat the purpose, since one cat can guard or block the others. Distribute them across different rooms or different floors. Two cats, three boxes. Three cats, four boxes. Scoop daily, deep-clean weekly. Box hygiene matters as much as box number.

When to call a vet: if a cat suddenly stops using the litter box despite a correct setup, see your vet first — urinary issues or pain often present as litter box avoidance.