A wet patch where the cat was sleeping is incontinence; urine on a vertical surface is marking. The difference is posture and awareness, and it changes the entire workup. True incontinence in cats most often means the urethral sphincter is too weak to hold urine in, and a large share of those cases respond to medication within 2 to 4 weeks. It is not a litter box problem, and punishing the cat makes it worse.
The postural test
Watch, don't guess. A cat with incontinence leaks while lying down, sleeping, or being lifted, and often wakes up in a wet spot with urine on the fur of the hind legs and perineum. There is no squat, no tail lift, no scratching afterward. A cat that marks backs up to a wall or door, holds its tail high and quivers it, sprays a small volume at nose height, and walks away dry.
Volume and timing help too. Incontinence tends to be a steady dribble that is worse after rest or after a long sleep, and the cat may groom the area constantly. Marking comes in small amounts, often at fixed times of day, and is directed at vertical surfaces near doors and windows. Litter box avoidance is a third pattern — full bladder, normal posture, wrong location — covered in litter box avoidance.
Urethral sphincter mechanism incompetence
This is the most common cause in middle-aged and older spayed females, and it is hormone-related: removing the ovaries removes the hormonal support that keeps the smooth muscle of the urethra toned. The bladder fills normally and the cat urinates normally, but between visits the seal gives way, especially when the cat relaxes deeply in sleep.
It is diagnosed by exclusion, and response to treatment is part of the diagnosis. A cat that stops leaking on phenylpropanolamine within 2 weeks almost certainly had sphincter incompetence. Body weight matters: losing 10% to 15% of body weight in an overweight cat often reduces leakage on its own, because abdominal fat presses on the bladder.
Nerve damage: tail pull, fracture, surgery
The nerve supply to the bladder and sphincter runs through the sacrum, so a tail injury can cost bladder control. A cat that was pulled by the tail, hit by a car, or fell from height may have a sacral fracture or a stretched pudendal nerve. Look for a floppy tail, a perineum that does not respond when pinched, and a bladder that is either too easy or impossible to express.
Some cats leak after perineal urethrostomy, the surgery done for repeated urethral blockage, because the sphincter is partly bypassed. That is a known trade-off, and it is manageable with the same drugs and diaper routine. Manx and other tailless breeds can have sacral malformation and leak from a young age. Cats with spinal arthritis may also dribble because they cannot posture comfortably.
Bladder overactivity and the rest of the list
An irritated bladder contracts before it is full. Urinary tract infection, bladder stones, cystitis, and bladder tumors all do this, and the result is frequent small urinations, sometimes with blood, plus leakage between trips. Any cat with new incontinence needs a urinalysis and a culture, because an infection on top of sphincter weakness is common and treatable.
Also check: diabetes mellitus, which produces large volumes and overflow; chronic kidney disease (CKD), same pattern; hyperthyroidism in older cats; and constipation, where a full colon presses on the bladder. A cat that strains and produces only drops may have a blockage, which is a different emergency — see urinary blockage signs.
The workup
| Step | What it finds |
|---|---|
| Urinalysis | Infection, crystals, blood, dilute urine, glucose |
| Urine culture | Bacteria that a dipstick misses |
| Bladder scan or palpation after voiding | Residual volume: over 10 ml suggests retention |
| Neurologic exam | Tail tone, perineal reflex, anal tone, proprioception |
| Bloodwork | Kidney values, glucose, thyroid, electrolytes |
| Radiographs or ultrasound | Stones, sacral fracture, bladder wall thickening |
Keep a 3-day log of when the cat leaks and how much. A log that shows leakage only during deep sleep points at the sphincter; leakage right after voiding points at the bladder.
Drugs that help
Phenylpropanolamine at 1 to 1.5 mg per kg two to three times daily is first line for sphincter weakness and works in most cats within 2 weeks. Pseudoephedrine is used as a cheaper substitute in some countries at roughly 1 mg per kg twice daily, but it is less predictable and harder to dose in a cat. Imipramine at 5 to 10 mg per cat once daily, or 2.5 to 5 mg twice daily, adds urethral tone and calms bladder contractions.
Estriol, a weak estrogen, is used in some spayed females at 0.5 to 1 mg per cat per week, but it carries a bone marrow suppression risk and is falling out of favor. Bethanechol can help a bladder that will not contract, though it must never be used when there is an obstruction. Expect a 4 to 6 week trial before deciding a drug is not working, and check blood pressure on phenylpropanolamine.
Living with it: diapers and skin
Cat diapers work if sized by waist measurement, not by weight, and changed every 4 to 6 hours. Cut a hole for the tail, use a suspender-style harness so it does not slide, and expect the cat to need 1 to 2 weeks to accept it. Wash the skin with plain warm water at each change, dry fully, then apply a barrier cream with zinc oxide.
Urine scald is the real risk: red, raw skin along the inner thighs and around the perineum, which becomes infected fast. Clip the fur short in that area with a quiet clipper, not scissors. Wash bedding at 60°C, use waterproof pads under the cat's favorite sleeping spots, and put down 4 to 6 more absorbent pads than you think you need. A cat that cannot stay dry needs a vet visit, not a stronger detergent.
What to do this week
- Watch one episode and note posture: lying down or standing with tail up.
- Catch a urine sample in a clean container and drop it off within 2 hours.
- Weigh the cat. If it is overweight, a 10% loss target is part of treatment.
- Add one litter box per floor and keep the existing one scrupulously clean.
- Ask specifically for a neurologic exam of the tail and perineum at the next visit.
Frequently asked
Can incontinence be cured, or only managed?
Sphincter weakness is usually managed rather than cured: medication controls it in most cats, but stopping the drug brings the leaking back. Nerve damage from a fracture sometimes recovers over 3 to 6 months as swelling settles. Cases caused by infection or stones can resolve completely once the trigger is treated.
Is it cruel to use diapers on a cat?
Not if they fit and are changed often. Most cats accept a diaper within 1 to 2 weeks, and a properly sized one does not restrict walking or jumping. The bigger welfare issue is wet skin and urine scald, which is why changes every 4 to 6 hours and a barrier cream matter more than the diaper itself.
Should I restrict water to reduce leaking?
No. Restricting water concentrates urine, raises the risk of crystals and infection, and can harm the kidneys, especially in a cat with chronic kidney disease. Cats with incontinence need normal water intake and wet food. Managing the leaking is about the sphincter, not about how much the cat drinks.