August 2019

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

If you don't find urine in the litter box there can be a few reasons, and we will help you trouble shoot.

Before attributing this to a behavior reason, we must first consider medical reasons. The medical term for this condition is oliguria (abnormally small amount of urine) or anuria (no urinary output). Normal urinary output for a cat is about 0.25ml/kilogram body weight.

Medical Reasons

  • Urinary blockages: these can be seen in female and male cats and are an IMMEDIATE emergency-luckily, if addressed early enough, this is a treatable condition in most cases. A medical exam and in some cases imaging (X-ray or ultrasound) is needed to diagnose a blockage, and in most cases a urine analysis is needed to determine the cause of the blockage.
  • Dehydration or low blood pressure: this might be because the cat was not drinking enough. This can be determined by a medical exam and in some cases be confirmed with blood work and blood pressure measures. The urine may be very concentrated.
  • Kidney failure, shock, organ failure, or trauma: with these conditions chances are that the cat is very sick and an immediate exam by a veterinarian is needed.

It's also possible that your cat is actually urinating normal amounts, but it's undetected.

  • When you are using a non-clumping litter of any kind it can be sometimes difficult to verify how much the cat is actually eliminating. To remedy this, dump the litter and use fine granulated clumping litter. This will make it easier to actually see the urine amount (small clumps, normal clumps, number of clumps, or really no clumps).
  • The cat may be urinating in other places than the litter box provided. Use a black light to check for urine spots around your home. Then check if the litter box is easy accessible for the cat. Refer to the Litter Box Problems and Litter Box Tips handouts for tips on trouble shooting urinating outside the litter box.


  • 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®