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Innapropriate Indoor Toileting

by Dr. Emma Jones | Posted in: Cat Behaviour | Last Updated: 21 June 2021
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Is the cat marking or toileting?

Indoor marking/spraying behaviour can be confused with a breakdown in toileting behaviour.  Marking by urine spraying is usually performed standing with a raised tail against vertical objects such as chairs or walls and can be distinguished from urination/voiding where a greater volume of liquid is deposited from a squatting position.  Urine spraying along with scratching, rubbing, bunting and middening (leaving faeces uncovered) are part of the cat’s normal scent-marking repertoire used to mark territory.  The approach to inappropriate indoor marking/spraying is a separate issue and will be discussed in another handout. 

Note: Punishing cats for inappropriate toileting does not work.  If caught in the act they can be picked up and placed on the litter tray, stroked and calmed.  Frightening the cat will make it nervous and even more likely to toilet indoors – just in places harder to find.

One of the reasons cats make good pets is that they usually learn very early and with little effort that our homes are not toilets.  Kittens almost instinctively head for the litter tray at a few weeks of age and usually make the transfer fully to the garden once allowed out.  Some individuals take longer to learn than others and some can be difficult to establish as house trained. Some cats will require a litter tray in addition to outdoor access, for life.  It is not a bad idea even in outdoor toileting cats to provide a litter tray at all times – just in case.

Why do cats toilet indoors?

A cat with normally clean indoor behaviour may begin to urinate indoors as a result of illness, stress/anxiety or urinary tract disease.  Some may fail to re-establish their previous clean behaviour.  Correct diagnosis of the inciting cause can help determine the best treatment strategy for a speedy resolution.

Medical problems should be ruled out first. The most common causes are urinary tract infections, urinary crystals (+/- stones) and stress induced inflammation of the bladder. 

Your veterinarian will initially ask many questions to get an understanding of your cat’s environment and situation at home. Usually we require a urine sample. The presence of red blood cells, excessive white blood cells, crystals, altered pH, high protein content or a lowered concentration of the urine indicate a problem that may require medical management. Often a urine sample will need to be sent to the laboratory for microscopic examination of the sediment, or for culture. If kidney or bladder stones are suspected a radiograph may be taken.  In older cats or where other abnormalities are found on clinical examination, a blood sample will be recommended as organ dysfunction such as kidney disease or diabetes may be suspected.  


Treatment depends on the cause. Bladder infections will be treated with antibiotics and anti-inflammatory medication. Crystals are dissolved and prevented in future using appropriate diets for the type of crystal present.  Anti-inflammatories are also used initially, and weight loss is also important.  If bladder stones are present, these may be removed surgically, or dissolved by diet with on-going monitoring. Lower urinary tract inflammation without the presence of infection or crystals and a history that suggests the presence of stressors may be treated with anti-inflammatories, diet modification, environmental modification and sometimes anti-anxiety medications. 

Where urine and blood samples are normal, a behaviour problem is the likely cause.  Several aspects of the cat''s environment can be altered to try and treat the problem sometimes in conjunction with behaviour-modifying drugs.

The litter tray

Number and size - One tray per cat plus one extra is a good guide, as many cats do not like to share trays.  Having trays in different rooms also helps.  Ensure the litter tray is large enough for the cat to comfortably fit into.  Many trays are designed for kittens and are too small for the average sized cat.  High sides are beneficial to prevent the cat ‘missing’ the box, however if there are mobility issues consider ramps or there are boxes available that have a lowered entry.  

Types of litter - Cats often have a litter preference and problems may arise if the type of litter is changed.  A gradual change by mixing litters is recommended if you want to change types.  There are several different types of litter such as clay, wood chip pellet, recycled newspaper pellet and waxed granule varieties.  You could use sand, or if the cat also toilets outdoors the litter can be mixed with soil. 

Cleaning - Cats are fairly fastidious and can reject a litter tray if it is deemed too dirty.  Change the litter daily and remove solids whenever they are seen.  Avoid using strong chemical cleaners as these smells can put cats off too.  

Security and position - Position the litter tray in a secluded private area away from main pathways through the house.  Some cats prefer covered trays, others prefer open.  Try simply covering the tray with a large box with a hole cut out for entry/exit.  Formed covered trays are available from pet shops.  Do not place litter trays close too food and water bowls.

Litter tray training/retraining

Confine the cat in a crate in a small room with only enough space for a bed, food and water bowls and a litter tray.  The desire to avoid soiling the bed is established early in life and he or she should move as far away from the bed as possible to eliminate and this will mean using the litter tray.  Hopefully within a few days the cat should again being to associate toileting with the litter tray.  The cat should be kept in the cage indoors at all times when the owner is unable to supervise.  After a couple of days of ''good aim'' the cat can be allowed out of the cage only into the room where it is kept and the litter tray moved progressively further away from the bed.  Access to the rest of the house should be allowed one room at a time and only under supervision for the initial introduction to each room.  Before allowing access back to the house, all previous unwanted toileting areas should be thoroughly cleaned using a proprietary ''urine digester'' or a warm solution of a biological washing powder or liquid followed by a light scrubbing with an alcohol such as surgical spirit.  (check that cleaning does not remove colour from carpet etc.) The area should be left to dry thoroughly before supervised access is allowed.  

Behaviour Modifying Drugs

The speed and success of treatment may be assisted by the use of certain drugs where inappropriate toileting is due to anxiety or inter-cat conflict.  This option should be discussed with your vet and used in conjunction with behavioural modification techniques.

How can I prevent future urinary problems? 

Lower urinary tract disease is more common in cats that have lower water consumption, are inactive and obese. Avoiding obesity and encouraging exercise and water consumption go a long way to preventing recurrent problems.  Including some wet (pouch or canned) food in the diet is an easy way of increasing water consumption, and also ensure water bowls are easily accessible, full and clean at all times.

 If your cat has been prescribed a special diet to dissolve and prevent crystal formation, it is important that you continue to feed the recommended product.  There are currently multiple diets produced for dissolving crystals, in both wet and dry form and most cats can be successfully transitioned onto them.  Once urine tests are negative for crystals a maintenance diet should be fed for life to prevent crystal recurrence. 

Altering the environment to reduce stressors is important for feline bladder health.  Continue to provide a litter tray if possible even if it is not used very often.  Provide vertical escape space in multi-cat households and multiple food/water stations.  Inter-cat aggression can be very subtle to the human eye.  The use of pheromone products such as Feliway can help anxious cats cope with change – e.g. new furniture.  There are many websites dedicated to providing information on creating a cat-friendly environment in the home.