August 2019

Audience: Executive Leadership, Foster Caregivers, Public, Shelter/Rescue Staff & Volunteers, Veterinary Team

If your cat is urinating or defecating outside the litter box, we certainly understand your frustration. Luckily, this is a treatable condition in most cases. A medical exam, as well as a few simple changes can help to re-establish proper litter box use.

The first step includes taking your cat to your veterinarian. Whenever a cat suddenly eliminates outside of the litter box, it's strongly advised to get a physical exam including urine analysis and in some cases blood work in order to rule out any illness or injury that may be causing the behavior. Once a medical reason for the lapse in litter box use has been ruled out, you want to consider behavioral reasons.

There are two main behavioral reasons for failure to eliminate in an established litter box. One is marking, which is a form of communication. The second one is inappropriate elimination, which is a toileting behavior. Both behaviors may occur for a variety of reasons. See handout for these litter box problems.

No matter the reason, there are a few litter box tips that are universally important to all cats.

  • Always keep the litter box clean. Scoop the litter box at least once daily and completely empty and clean it with mild dishwashing liquid weekly.
  • The magic number is one litter box per cat in the household, plus one extra-these litter boxes should be in different rooms to count as separate litter boxes. Two litter boxes right next to each other count as one.
  • If you have a multi-story house, have litter boxes on each level.
  • Make previously marked areas unavailable (close doors to certain rooms).
  • Keep litter boxes away from food and water bowls, as well as the washer and dryer.
  • Clean all soiled areas with an enzymatic cleanser.
  • Use a black light to help you locate all the spots in your house; urine will glow yellow-green in the dark.
  • Offer different types of litter to find your cat's preferred litter: Clumping, non-clumping, sand, clay. Use a fine granulated type of litter so the surface is soft and deep.
  • Type of litter box: Most cats dislike covered litter boxes, especially in multi-cat households. Also, many commercially available litter boxes are simply too small for an average-sized cat, let alone a large cat. The litter box should be at least 1.5 times the length and width of your cat. If your cat is too large for "jumbo" litter boxes available at pet stores (and many, if not most, are), many people are successful using a large plastic storage bin with a "door" cut into it or under-the-bed storage bins, which have lower sides and may not need to be cut.
  • Do not use litter box liners, harsh detergents, or scented litters.
  • Depth of litter: Most cats prefer to have several inches of litter to dig around. Experiment to find your cat's preference.


  • Always begin by consulting your veterinarian to rule out medical causes.
  • Check all the above guidelines as every cat and situation is different.
  • VERY IMPORTANT: Do not punish your cat for marking as this will not solve the problem; this can make your cat even more anxious.

This document created by the San Francisco SPCA with a grant from Maddie's Fund®