A cat who has started going outside the box is the most common behavioral reason cats get rehomed, and that is a tragedy built on a misunderstanding. Owners read it as protest, or as a bad habit. It is far more often a cat telling you that something hurts, or that the box itself has become unusable. Both of those are fixable.
Rule out the body first
This is the order that matters, and getting it backwards is why so many of these go unsolved for years. Before anyone settles on a litter or box change as the answer, the cat needs to be examined, because a surprising share of litter box problems are medical.
- A painful bladder. Inflammation makes urinating hurt, the cat associates the box with the pain, and goes somewhere else. Small puddles in odd places, straining, and licking at the back end point here.
- A blockage, which in a male cat is a genuine emergency. A cat straining in the box and producing nothing needs to be seen immediately, not a new litter.
- Anything causing more urine. Failing kidneys, diabetes and an overactive thyroid all increase output. The box fills faster than it used to, reaches a state the cat will not use, and the cat finds a clean alternative. The box was never the problem.
- Sore joints. This is the one most often missed in older cats. A cat with stiff hips cannot climb into a high-sided box, cannot hold a crouch comfortably, and cannot get down the stairs to the basement box at three in the morning. We wrote about night waking in older pets separately, and the same joints are usually behind both.
- Constipation, which makes the box an unpleasant place for its own reasons.
- Cognitive change in a very old cat, where the box simply stops being found reliably.
An examination here covers that, and in-house blood and urine testing is what separates those causes from each other, usually during the same visit. A cat straining without producing urine goes through urgent care immediately.
One distinction worth bringing with you: squatting and leaving a puddle on a flat surface is usually about the box or the body. Backing up to a vertical surface with a quivering tail and leaving a small amount at nose height is spraying, which is a different behavior with different causes. A cat can also mark from a squat, though, and a target like your bed points that way.
Then fix the box
Once the body is cleared, the box itself is where the answers are, and apartment living stacks the odds against most of them.
- One box per cat, plus one. Two cats need three. This is the single most common shortfall, and in a one-bedroom it feels absurd until it works.
- Bigger than you think. A box should be about one and a half times the length of the cat, nose to tail base. Most boxes sold are too small, and a large plastic storage tub is better than anything in the pet aisle.
- Take the lid off. Hoods trap odor for the cat as much as for you, and they remove the escape routes a cat wants.
- Low sides for an older cat. If your cat is over ten, cut one side down or buy a box with a low entry. This alone resolves a good number of senior cases.
- Unscented, fine-grained clumping litter, about one to two inches deep. Most cats prefer it and most perfumed litters are chosen by people.
- Scoop daily, and wash the box weekly with warm water and unscented soap. Skip the strong disinfectants and never use anything ammonia-based, which smells like urine to a cat.
- Location matters more than decor. Not beside the washing machine, not in a closet a door can close on, not somewhere the dog or another cat can corner them. Boxes on more than one level if you have stairs.
- Skip the liners, which catch claws and put cats off.
The stress layer
If the body is clear and the boxes are right, what is left is usually social or environmental, and in a dense building there is plenty of it: a new cat, a new baby, a new neighbor’s cat visible through a window, building work, a move, or a change in who is home and when.
What helps is giving the cat more space in three dimensions rather than more floor: shelves, a cat tree, somewhere high to sit and watch. In a multi-cat home, separate feeding stations and more than one route through each room matter more than toys. Covering the bottom of a window a strange cat patrols can resolve a months-long problem in an afternoon.
Two things to avoid. Do not punish, including the gentler versions — being carried to the box, or scolded at the spot. It increases anxiety, and anxiety is frequently the driver. And clean soiled areas with an enzyme cleaner rather than a household one, because the goal is removing the scent entirely rather than covering it.
Our hours
We are open Monday through Saturday from 8:30 am to 7:00 pm and Sunday from 9:00 am to 7:00 pm, seven days a week.
A cat going outside the box is an appointment rather than an emergency, with one exception: a cat straining and producing nothing, particularly a male, needs to be seen immediately. If that happens outside our hours, our after-hours referral partner is Ocean Avenue Veterinary Hospital at 415-586-5327, 1001 Ocean Avenue, open around the clock.
Common questions
My cat only does it when we go away. Is that spite?
No. It is anxiety and a disrupted routine, and often a box that nobody scooped for three days. Both are addressable, and a sitter who scoops daily fixes more of these than anything else.
Do I need to bring a urine sample?
If you can catch one, yes, and it saves a step. Non-absorbent litter works, or an empty clean box. Collect it the morning of the visit and keep it cool.
Should I shut my cat in one room with the box?
Sometimes, briefly, as part of a plan rather than as the plan. Confining a cat whose problem is physical just moves the puddle somewhere you cannot see it.
My older cat has started going right beside the box.
That is a classic sign the box is physically hard to use rather than unwanted. Think joints and box height before anything else, and mention it to us.
Does more than one cat make this inevitable?
Not inevitable, but multi-cat homes do account for a lot of it. Boxes, vertical space and separate feeding are what make a shared apartment work.
Speak to the team at SF Vet Hospital
Book an examination before you change the litter. Bring a urine sample if you can catch one, and a note of where the accidents are happening and on what surface. That map is more diagnostic than it sounds.
Published by the team at SF Vet Hospital.
This article is educational in nature and is not a replacement for hands-on assessment of your own pet by a veterinarian.
SF Vet Hospital
2001 Harrison Street, San Francisco, CA 94110 (Mission District)
Phone: (415) 907-7576
Hours: Monday to Saturday 8:30 am to 7:00 pm; Sunday 9:00 am to 7:00 pm