SYMPTOM
Indoor urine spraying or marking
A cat backs up to a vertical surface, such as a wall, curtain or piece of furniture, with tail raised and quivering, and releases a small amount of urine, or a dog repeatedly lifts a leg against vertical objects, or squats, to leave small amounts of urine around the home.
Normal Territorial Or Social Marking
Marking with urine is a normal communication behaviour in both cats and dogs, used to signal territory or social status, particularly in multi-cat households or homes near other cats' outdoor territory. It is not itself a disease process, and unneutered animals of both sexes are more likely to mark for this reason alone.
Lower Urinary Tract Discomfort
Feline idiopathic cystitis, a urinary tract infection, or bladder stones can cause pain or a frequent need to urinate that leads a cat to associate the litter tray with discomfort. This can produce house soiling or spraying-like behaviour that is frequently confused with purely social marking. In male cats, cystitis or stones can block the urethra, which shows as repeated straining with little or no urine passed.
Intact Reproductive Status
Unneutered male cats in particular are strongly predisposed to spraying pungent, hormonally driven urine as a mating and territorial signal, and unneutered females may mark more during seasons. The behaviour typically reduces, though does not always fully resolve, after neutering.
Household Stress Or Social Conflict
A new pet, a house move, altered furniture layout, or tension between cats in a multi-cat household are recognised triggers for an increase in marking. This reflects anxiety or social conflict rather than a urinary or reproductive cause.
Litter Tray Aversion
A tray that is too small, not cleaned frequently enough, in an exposed location, or recently changed in litter type can lead a cat to eliminate, rather than truly mark, in other locations around the home. Owners often describe this using the same language as spraying, even though the underlying behaviour is distinct.
Cognitive Decline In Older Animals
In senior cats and dogs, house soiling can reflect disorientation or a loss of previously reliable toileting habits rather than a purposeful marking or medical urinary signal. It often appears alongside other behavioural changes such as altered sleep patterns or reduced awareness of surroundings.
Why timing matters
Early observation
A newly started pattern of marking or house soiling is generally easier to trace to its trigger, whether a household change, an unneutered status, or the very first signs of urinary discomfort, while the context is still fresh. Documenting the pattern from the outset makes this tracing considerably more reliable.
Later presentation
An established pattern that has continued for weeks or months becomes harder to unpick, partly because the behaviour itself can become a learned habit that persists even after the original trigger has been addressed. By this stage, the location and frequency of marking may reflect learned preference as much as the original cause.
Because purely behavioural marking and pain-driven house soiling can look identical to an observer, the distinction usually rests on associated detail, such as frequency, blood in the urine or a clear behavioural trigger, rather than on the act of marking itself. Straining that produces little or no urine is a separate picture, because it can mean a blocked urethra. This is why characterising the surrounding pattern matters more than the single observed event.
Conditions commonly associated
Urine Marking in Cats
This is the clinical term for the normal territorial and communicative urine-marking behaviour itself, distinct from house soiling caused by an underlying medical problem.
Feline Idiopathic Cystitis
Bladder wall inflammation without an identifiable infection is a common cause of urinary discomfort in cats that can lead to house soiling or spraying-like behaviour, particularly during stress.
Inappropriate Elimination in Cats
Distinct from true marking, this describes a cat toileting outside the litter tray, often linked to tray aversion, medical discomfort or environmental stress rather than territorial signalling.
Anxiety Disorders in Cats
Underlying anxiety, whether generalised or triggered by a specific household change, is a recognised driver of increased marking behaviour.
The page on this condition is being checked again and is offline for now.
Inter-Cat Aggression
Tension or conflict between cats sharing a household is a common trigger for increased territorial marking by one or more of the cats involved.
Canine Cognitive Dysfunction
Age-related cognitive decline can lead to disorientation and a breakdown of previously reliable house-training in older dogs.
Urinary Tract Infection in Dogs
Infection within the urinary tract can increase the frequency of urination and the need to pass urine in dogs, sometimes presenting as increased indoor marking-like behaviour.
Urethral Obstruction
In male cats, cystitis or stones can block the urethra. The cat strains repeatedly and passes little or no urine, which can be mistaken for marking or soiling.
Feline Cognitive Dysfunction
Age-related cognitive decline in older cats can lead to disorientation and a breakdown of previously reliable litter tray habits.
When to explore further
A previously reliable cat begins marking or soiling for the first time, particularly if the change is sudden rather than a longstanding habit
A cat, particularly a male, makes repeated attempts to urinate and passes only drops or nothing, cries while straining, licks at the genital area, vomits or seems flat: these are the signs of a blocked urethra, which International Cat Care states can cause kidney failure and be fatal within 2 to 3 days without treatment, and which can be hard to tell apart at home from cystitis or constipation
The pattern coincides closely with an identifiable household change, such as a new pet, a house move, or a change in litter or tray location
Blood is visible in the urine
The behaviour appears for the first time in an older animal alongside other changes in routine, sleep pattern or awareness of surroundings
A log noting exactly where in the home marking occurs, at what time of day, and whether it coincides with anything observable outside, such as another cat visible through a window or a change in routine, helps separate territorial from stress-driven marking. Watching whether the cat uses the litter tray normally at other times, and noting the frequency and volume of urine passed, helps distinguish a urinary component from pure behaviour. Straining that produces little or no urine is not a pattern to log over days, as a blocked bladder cannot be ruled out at home. For multi-pet households, recording which individual is responsible (sometimes only identifiable by direct observation) matters, because the rest of the log only helps if it describes the right animal.
Last reviewed: 9 October 2026 · Dr Alastair Greenway MRCVS