We have two cats who are both allowed outside. Our cat-flap is one of the fancy ones that authenticates the cat using its ID chip, but sometimes it doesn't shut properly and one of the neighbours' cats has taken to coming in and making himself at home. We chase him out whenever we see him inside, but he has yet to take the hint.

Sometimes we come home (or come downstairs in the morning) to discover that a cat has sprayed in the kitchen. We're assuming it's the visitor. Is there any way to discourage the visits, or at least discourage the spraying?

  • 2
    Ugh. Sounds like your cat-flap is in need of some sort of repair. Dec 15, 2013 at 22:55
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    It could be one of your cats, trying to discourage the visitor by marking their territory. My advice would be to remove the catflap and keep your cats indoors only.
    – Zaralynda
    Dec 15, 2013 at 23:09
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    I am not sure that you have sufficient evidence that it is the neighbor cat. It may be your cats "helping" to remind the neighbor cat who owns the house. If possible lock the door at night, to see if you find spray when only your cats had access. Particularly if it is a night after the neighbor gained access during the day. Dec 16, 2013 at 10:19

1 Answer 1


The first and most obvious step here is to fix or replace the cat flap as soon as possible. If the neighbor's cat can't get in, he can't spray inside the house. Do this first because any cleaning you do will just get sprayed over (Obviously, you need to clean enough that your nose can't pick up the cat pee smell).

If the neighbor's cat is the culprit, there's a fair chance your cats will spray over the top to reclaim the area as their territory. If one (or both) of your cats is spraying to tell the interloper who "owns" the territory, they will continue to mark until they can't smell the interloper.

To deal with that delightful little issue, you're going to need a black light torch to find every place that's been sprayed. You'll need to clean the whole house with an odor neutralizer, but the sprayed surfaces will need extra attention. Don't use anything with chlorine (many cats react to chlorine the same way they'd respond to catnip, and you don't need your cats associating the marked spots with getting high) or ammonia (since that's one of the major components of urine, any cleaning product containing ammonia could smell enough like marked territory to convince a persistent marker that he (it's usually a he, although females can also spray) needs to freshen up his scent in the area). An oxygen bleach (cheaper) or specially formulated cat odor neutralizer is probably your best bet - make sure you get plenty of it, because it's likely you'll need to do this several times before the problems stop. (I won't list products because I'm in the USA and you're using UK/Australian spelling, so you're probably not going to be able to get anything I recommend anyway)

Once you've inspected with black light and cleaned, wait a day or so, then get someone with a good sense of smell to prowl the house sniffing for cat pee. It's amazing the places cats will find to mark: you're likely to find the remains of marking in all sorts of odd corners.

Good luck. I've suffered through this myself, and it's not fun.

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    If carpet is involved, a black light might not help. My black light illuminated cat urine on other surfaces (walls, linoleum, etc.), but would not reveal urine on our carpet for whatever reason. At any rate, your best bet is to find a product that has enzymes that are formulated for destroying the odor causing component of cat urine. Unless this is destroyed, the smell will come back any time the area becomes damp.
    – cimmanon
    Dec 16, 2013 at 17:55
  • @cimmanon - good point! I've never had to search out cat urine in carpet, so that never occurred to me.
    – Kate Paulk
    Dec 17, 2013 at 12:46

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