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Emergency first: if a male cat is straining in the litter box, going back and forth, crying, or producing little or no urine, treat it as a same-hour emergency and go to a vet now. A blocked urethra can be fatal within days. Do not wait to see if it passes.
The short answer: a cat peeing outside the litter box has one of four basic causes: a medical problem, a painful bladder condition called feline idiopathic cystitis, marking, or an environmental or social trigger. Not spite. Start with a vet exam and urine test, because cats with medical causes often do not look sick. If the vet finds nothing, fix the box: two boxes in two places even for one cat, each 1.5 times the cat's length, uncovered, with at least 1.25 inches of fine unscented clumping litter, scooped daily. Check where the urine lands: a puddle on a flat surface is urination, a small spot up a wall is spraying.
Written by Marc Brannigan, Co-Founder & CEO of HempMy Pet. Last updated 28 October 2026.
Three Questions That Sort Most Cases
Answer these before you buy anything.
A puddle on a flat surface is ordinary urination in the wrong place. Small amounts on a wall, door or furniture, with the cat standing, tail up and quivering, is spraying. Carney et al. 2014 note the cat can spray and still use the box normally.
Straining, small frequent amounts, blood, crying in the box, licking the genitals, or drinking and urinating far more than usual all mean call the vet. These point to bladder, kidney or metabolic disease.
A new cat or baby, a move, new litter, a moved or cracked box, a changed work schedule, or an outdoor cat at the window. House soiling often starts after a change the owner did not link to the cat.
Cat Peeing Outside the Litter Box: Eight Causes Side by Side
Grouped under the four causes in the AAFP/ISFM house-soiling guidelines (Carney et al. 2014), with Cornell's behavioral categories.
| Cause | What it looks like | The tell that separates it |
|---|---|---|
| 1. Urinary tract disease (infection, stones, feline idiopathic cystitis) | Frequent small urinations, straining, blood, urinating outside the box in a sudden change | Pain around urination; vet urinalysis and culture needed. No single test confirms cystitis. |
| 2. Other medical disease (kidney disease, diabetes, hyperthyroidism) | Large puddles, more thirst, weight loss despite eating, mostly in older cats | Increased drinking and urinating; bloodwork picks it up. |
| 3. Pain or mobility problems (arthritis, orthopedic) | Peeing next to or near the box; skipping a box with high sides or on another floor | The cat reaches the box area but cannot or will not step in; may also stop jumping. |
| 4. Box problem (dirty, too small, covered, wrong litter) | Peeing on the floor beside the box, or avoiding it entirely | Improves when the box is cleaned, enlarged or uncovered. |
| 5. Box location problem (noise, traffic, next to food, ambush spots) | Using the box at some hours but not others, or peeing near a better spot | Fine in a quiet room; fails near the washer, cat door or food bowls. |
| 6. Surface or site preference | Repeated use of one soft or smooth surface, such as carpet, bedding or tile | Same spot every time, usually horizontal. |
| 7. Marking (spraying) | Small amounts on vertical surfaces, tail up and quivering | Standing posture; the cat may still use the box normally. |
| 8. Stress or social conflict | Peeing in new places after a change, or one cat blocking another from the box | Timing matches a change; in multi-cat homes a dominant cat may guard the box. |
Sources: AAFP/ISFM house-soiling guidelines (Carney et al. 2014); Cornell Feline Health Center. Cornell reports that about 10% of neutered males and 5% of neutered females spray, and that in homes with more than seven cats one or more will likely spray.
What the Vet Will Check
The AAFP/ISFM guidelines set a minimum workup for urine problems: a urinalysis with sediment exam, a urine culture collected by cystocentesis, and imaging of the lower urinary tract. If the urine is consistently dilute (specific gravity below 1.030), the vet adds a blood count and chemistry, plus a thyroid (T4) test in cats over 8. Every case gets a physical exam including orthopedic and neurologic assessment. For faeces the list is separate: a faecal exam, a rectal exam and bloodwork.
Two points worth knowing before the appointment. Antibiotics should not be used without a positive urine culture. And in feline idiopathic cystitis, the panel reports that changing the cat's environment (the "multimodal environmental modification" approach) significantly decreased signs and lengthened the time between flare-ups in chronic cases, while pentosan polysulfate showed no benefit over placebo.
Set the Box Up Properly: The Numbers
If the vet finds no medical cause, the box is the next suspect.
| Setting | Recommendation | Source |
|---|---|---|
| Number of boxes | Two boxes in two separate locations for a single cat; at least one more box than cats in a multi-cat home; at least one per floor | Carney et al. 2014 |
| Size | 1.5 times the cat's length, nose to base of tail; "bigger is better." One study found adult cats preferred a 34 × 15 inch box | Carney et al. 2014 |
| Litter | Fine, unscented, clumping, sand-like, at least 1.25 inches deep. Avoid liners, slotted grills and deodorizing powders | Carney et al. 2014 |
| Covered or open | Open preferred; cats split evenly on covers, and cleaning frequency may matter more. Small covered boxes can hinder large cats | Carney et al. 2014 |
| Location | Quiet, private, easy to reach, away from food and water, noisy appliances and cat doors; openings should not face each other | Carney et al. 2014 |
| Scooping and washing | Remove waste at least daily; wash the box every 1–4 weeks with soap and hot water only | Carney et al. 2014 |
| Moving a box | Once a cat uses a box, keep it in the same place for at least 2 weeks; move it gradually | Carney et al. 2014 / Cornell |
| Low sides | For kittens, elderly cats and cats with mobility problems | Cornell |
Offer more than one litter or depth in different boxes and see which the cat picks. If a cat is guarding the box in a multi-cat home, add stations in separate rooms rather than side by side.
How to Clean Urine So the Cat Stops Returning
- Find every spot. Urine fluoresces under a black light. Clean an area up to three times the diameter of the visible patch.
- Use a biological cleaner. On carpet the guidelines suggest a 10% biological washing powder solution, drying, then isopropyl alcohol. Test a hidden patch first.
- Avoid ammonia. It smells like urine to a cat. Keep strong chemicals out of the litter box too.
- Make the spot less appealing. Cornell suggests blocking access, covering the area, or putting food bowls or toys there.
- Do not punish. Both sources say it raises anxiety and makes the problem worse.
Where Hemp Fits — and Where It Doesn't
No study has tested hemp or CBD for house soiling, spraying or cystitis. Medical causes need a vet exam, a urine test and often a prescription. Hemp is never a substitute.
Once medical causes are ruled out and the box is fixed, some owners add a cat-specific serving of full-spectrum hemp to help support a calm routine during a move, a new pet or a schedule change. See hemp for cat anxiety.
If sore joints are why a senior skips a high-sided box, a low-entry box comes first. Owners also use a low serving of hemp to help support comfort and easy movement. See hemp for senior cats.
The honest limit: the evidence for hemp in cats is thin, and cats process hemp differently from dogs. Read why cats process hemp differently and whether CBD is safe for cats, use weight-based servings from our cat serving guide, and talk to your vet first if your cat takes medication. The 93% result in the author box is from a dog joint trial, not a cat trial. For how long cats typically live and what to watch in the senior years, see how long do cats live.
For a vet-checked cat with a stress-linked or senior-comfort need — not a urinary treatment
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Hemp for Cats → Cat Serving Guide
When to Call the Vet
Go now if:
- A male cat is straining, crying or producing little or no urine
- Blood in the urine, or a cat that is lethargic, vomiting or hiding
- Not eating or drinking for 24 hours
Book this week if:
- Any new peeing outside the box that lasts more than a day or two
- Drinking and urinating much more than usual, or weight loss despite a good appetite
- An older cat avoiding the box, no longer jumping, or newly confused
- Spraying that does not stop after spaying or neutering and a box reset
Frequently Asked Questions
Why is my cat peeing on the floor all of a sudden?
A sudden change most often means something hurts or something changed. The AAFP/ISFM guidelines name four basic causes of house soiling: a medical problem, feline idiopathic cystitis (a painful bladder condition with no single identifiable cause), marking behavior, and an environmental or social trigger. Because cats with medical problems do not always look sick, the first step is a vet exam with a urinalysis, not a new litter. Kidney disease, thyroid disease, diabetes, arthritis and bladder stones are all on the guideline's rule-out list.
What smell will stop my cat from peeing?
None reliably does, and the guidelines advise against relying on deterrents. The AAFP/ISFM panel warns that noisemakers, mats and similar deterrents can add stress and may simply move the marking elsewhere. The more useful smell fact is about cleaning: avoid ammonia-based cleaners, because they smell like urine to a cat and can draw it back to the spot. The one scent product with studied evidence is a synthetic cat facial pheromone, which the guidelines cite as reducing urine spraying by up to 90% in studies; that applies to spraying, not to every case of peeing outside the box.
Where do cats usually pee in the house?
Two patterns. A cat that is urinating (squatting) usually picks a surface it prefers, and Cornell lists soft fabrics, carpet and smooth tile as common choices, or a location it prefers. A cat that is spraying stands, tail upright and quivering, and aims small amounts at vertical surfaces such as walls, doors and furniture. Where the urine lands is the first clue to which problem you have.
Why do cats pee outside the litter box when they have a UTI?
Because urinating hurts. Cornell notes that a cat can come to associate the litter box with pain and start avoiding it, even after the infection is treated. This is why the AAFP/ISFM guidelines say to rule out urinary disease first, with a urinalysis and a urine culture collected by cystocentesis, and why antibiotics should not be used without a positive culture. If your cat is straining, going often in small amounts or has blood in the urine, call your vet the same day.
Is my cat peeing outside the box out of spite?
No. None of the four causes in the veterinary guidelines is spite: they are medical disease, painful bladder inflammation, marking, and environmental or social stress. Cornell and the AAFP/ISFM panel both advise against punishment, including shouting, hitting or rubbing a cat's face in the mess, because it raises anxiety and can make the problem worse.
My cat pees outside the box but poops in it. What does that mean?
It points to a problem specific to urination, which makes a urinary cause or a preference for a different surface more likely than a general dislike of the box. The AAFP/ISFM guidelines set out separate minimum workups for urine and for faeces, so tell your vet exactly which one is happening. That detail narrows the search.
Why is my old cat peeing outside the litter box?
In older cats the medical list gets longer: kidney disease, hyperthyroidism, diabetes, arthritis and other orthopedic problems, and age-related cognitive change are all named by the guidelines or Cornell. A cat with sore hips or knees may avoid a box with high sides, so a low-entry box on the same floor as where the cat spends the day is a simple first fix. See our guide to why cats don't limp for how joint pain shows up.
How many litter boxes should I have?
The AAFP/ISFM guidelines recommend two boxes in two separate locations even for a single cat. In a multi-cat home the long-standing rule of thumb is at least one more box than the number of cats, though the panel says it is not absolute, and in a multilevel home there should be at least one box per level. Socially bonded cats may share, while cats that are not friends need separate stations.
How do I find out which cat is peeing in a multi-cat home?
Cornell suggests three methods: separate the cats for a short time, ask your vet for a non-toxic dye that colors the urine, or feed small pieces of non-toxic crayon to color the faeces. A video camera pointed at the problem area while you are out also works. Knowing who it is matters, because the cause can be medical for one cat and social for another.
How do I clean cat urine so the cat stops going back?
The AAFP/ISFM guidelines suggest finding every spot with a black light, since urine fluoresces, and cleaning an area up to three times the diameter of the visible wet patch. On carpet, scrub with a 10% biological washing powder solution, let it dry, then spray isopropyl alcohol; test on a hidden patch first. Avoid ammonia-based cleaners, which smell like urine to a cat.
Can hemp or CBD stop my cat peeing outside the litter box?
No study has tested hemp or CBD for house soiling, urine spraying or bladder disease, and we will not claim it. The most common reasons need a vet exam or a change to the box, the litter or the home. Where hemp can fit is as one part of a calm routine for a vet-checked cat whose problem is stress-linked, alongside the environmental changes above. Cats process hemp differently from dogs, so start with our cat serving guide and talk to your vet if your cat takes any medication.
Hemp for Cats → How Long Do Cats Live
Hemp for Cat Anxiety · Hemp for Senior Cats · Hip Dysplasia in Cats · Cat Yowling at Night · Is CBD Safe for Cats?
Marc co-founded HempMy Pet in 2016 with his business partner Natalie Mondine, the company's COO. HempMy Pet breeds its own hemp genetics, grows them on its certified-organic Colorado farm, and formulates every batch in-house under human-grade standards — seed to sale, nothing sourced overseas. Every batch is third-party tested and the certificates of analysis are published. More about us.
HempMy Pet ran its own 90-day study of 37 dogs with chronic joint discomfort. Of the 32 that completed it, 30 (93%) showed a benefit, and 94% of owners reported their dog's quality of life had improved. It was overseen by Dr. Robin Downing, DVM, MS of the Downing Center for Animal Pain Management, with Lori Kogan, Ph.D. and Peter W. Hellyer, DVM of Colorado State University's College of Veterinary Medicine & Biomedical Sciences, and published in the Journal of the American Holistic Veterinary Medical Association. Read the methodology.
Why Dr. Downing: in 2005 she became only the third veterinarian in the world credentialed as a Diplomate of the American Academy of Pain Management. She founded the International Veterinary Academy of Pain Management, is a Diplomate of the ACVSMR, a Certified Veterinary Pain Practitioner and a Certified Canine Rehabilitation Practitioner, and was the AVMA's 2020 Bustad Companion Animal Veterinarian of the Year. Chronic joint pain is her life's work. Read the published paper (PDF).
This article is general information for cat owners, not veterinary advice. It is reviewed and updated as new peer-reviewed evidence is published, and where the evidence is thin or negative we say so.
These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease. This article is general information, not veterinary advice. If your cat is unwell, contact your veterinarian.
