Cats can share quite a few things in the same home — food and water bowls, resting areas, toys… but what about litter boxes?
Everyone in your home shares the same toilet (or toilets) so it might be easy to assume that it's alright to have just one, but limiting litter boxes can result in trouble over time, like accidents around the house. Cats are known for being ultra-hygienic creatures, which means eliminating in a litter box that's already dirty with another cat's waste could be a deal breaker.
The short answer to the question at hand is, yes, cats definitely can share a litter box. Should they, however, is a more apt question, and will be determined by the number of cats using the box, the relationship between those cats, and possibly a few additional factors, like medical issues. Generally speaking, cats prefer to not use the bathroom where another cat has already eliminated, and may refuse to use a litter box if their own waste has been in there for too long.
Additionally, the ASPCA states that cats can become territorial over a litter box, preventing other cats from using it, which is obviously not ideal as our feline friends have to use the restroom somewhere. Cats who won't or can't use a litter box will often take to using the bathroom in other, far less ideal places around the home. In order to keep your cats safe and healthy, and your home clean and odor free, more than one litter box is best in a multi-cat household.
How many litter boxes do I need?
So, if cats should not share the same box, how many boxes should a home have? The number of litter boxes you'll need will depend on how many cats you have. As a general rule of thumb, it is recommended that a home provide one litter box per home, plus one extra litter box, says The Humane Society. So, if you have three cats. you should have four litter boxes total, and know that your cats will most likely rotate which box they use. The boxes should be placed in different locations around the home, all of which are easy to reach and turn around in.
Single litter box etiquette
If you live in a multi-cat household and absolutely cannot add another litter box to the space, there are a couple of things you can do to, hopefully, make the situation more accommodating for everyone. First, always be sure to keep the litter box as clean as possible — this means frequent scooping of pee and poop in the box, and regular wipe downs of the receptacle. Soap and water are great for cleaning, and vinegar or baking soda can help deodorize a litter box.
Next, make sure your litter box is placed in an area that all of your cats can easily access, and is large enough for everyone to fit in comfortably. If you have an older or arthritic cat in the home, or a kitten who may struggle to scale even the slightest obstacle, take extra care to make sure she can step in and out of the box. Finally, not all litter is created equal, and cats will usually develop a preference for a certain kind. To find the right cat litter, start with unscented litter and keep it shallow in the box — one to two inches should suffice in most cases.
Your multi-cat home can, technically, get by with just one litter box, but it's generally not recommended to limit more than one cat to a solitary box. Instead, provide one box for each cat in the home, plus one extra. Cats are a finicky bunch, and often won't eliminate in a dirty box, which can result in bathroom "accidents" around your home, or worse, medical side effects, like urinary tract infections.