The invention of kitty litter opened a new life style for cats.  Before, they lived outdoors as barn or alley cats -- afterward, they moved indoors to be house cats -- low-maintenance pets that no longer needed to go outside to relieve themselves.  The litter box design mimics so closely how they go outdoors, that mother cats can train their kittens to use one when they are just 18 days old! By the time you adopt a cat, the habit is ingrained.  All you need to do is show them their box, keep it clean, and that's it -- or is it?  Normally, cats are dependable litter-box users, but they may lapse under certain circumstances -- knowing what they are could head off a major problem.

Medical Causes.  If your cat eliminates outside the litter box, she may be ill.  About 25% of the time there is a medical reason -- typically a bladder infection.  A more serious problem -- especially for males -- is if the cat has bladder stones making urination painful or impossible.  If your cat strains to urinate, seek veterinary help at once -- this can be life-threatening.  Once diagnosed and medicated, stones can be managed through a special diet.  If the cat is elderly, geriatric issues may cause litter box lapses including chronic illness and even senility.

"Mechanical" Difficulties.  Sometimes a cat may use the litter box, but stands too close to the rim and goes over the side.  This is easy to correct.  Give the cat a hooded litter box and place a mat in front.

Litter Box "Alternatives" (from the cat's viewpoint).  Even a litter-faithful cat is tempted to wet articles laying on a floor like clothing, toys, bath towels and small rugs.  Some cats find open laundry baskets or papers left on a table equally satisfying.  All of these meet the litter box criteria -- absorbent materials that they can move around when they're finished.  The simplest solution is "good" housekeeping -- put things away when not in use.

Floor planters with loose soil are also an open invitation to a cat.  Keep your cat out of a planter by adding decorative stones to the top making it uncomfortable for the cat to stand on. 

If you find your cat regularly prefers alternatives to the litter box, rethink your box location -- or the type of box -- or your choice of litter.  In larger homes, provide a box on each floor.  Some cats prefer two litter boxes side-by-side so they can urinate in one and defecate in the other.  Make sure the litter is scooped daily and the boxes washed bi-weekly.

Litter-averse cats may prefer framed puppy training pads instead of -- or in addition to -- a standard litter box for urination.

Behavioral Problems.  When soiling is used to claim a territory, the behavior is "marking" -- typically vertical spraying of a wall or dropping of feces in very specific spots.  Any stress in the cat's life can trigger this -- a vacation or new home, another family pet or an animal outside -- even a particular person.  Although marking is distasteful to us, to cats it's a very natural behavior -- and often the soiled location points you to the cause.

To stop this, you need to eliminate the source of stress.  In the meantime, use an enzymatic cleaner (available from pet stores) to remove stains and odors from the area(s) -- then block the cat's access.  Cover the area with a plastic tarp or a large object.  Or place an empty (no litter) litter box on it -- the cat will prefer using the litter box making the clean up easier.  If the problem is limited to one room, close the door to keep the cat out.  Let her in only when you can supervise her -- and when you do, put "piddle pants" on her (see photo) so she wets a diaper instead of her target.

Putting a cat's food dish over the area may prevent soiling -- cats don't eliminate near their food. 

And, see a veterinarian -- you may be able to give anti-anxiety medication to help the cat calm down.

To solve litter box issues, focus on these principles:

Never punish the cat.  "Rubbing her nose in it" or other negative actions -- after you find an accident -- will only make the cat more anxious and fearful of you -- and could make the behavior worse! Cats learn only through positive reinforcement.  Try praising her when she does use her box and offer her a treat.  Make sure you give her quality time daily -- even if it's brief.

Stop the damage.  Seal off the area -- close off the room or confine the cat to a large dog crate with food, water and litter when you can't supervise her -- to stop the damage to your home.  This lowers your stress and makes it easier for you to focus on the problem -- and it reduces the size of your cat's territory which will make her less anxious.

Keep a diary.  Include the soiling locations, dates/times, if you were at home or away, any changes in the cat's life (new family member or pet, house guest) and a description of the soiling (amount, color, odor and texture).  Take this with you when you see a veterinarian.  The clearer the pattern and problem definition, the quicker you'll find the right solution.

Seek professional help.  Take your cat to a vet.  If no medical cause is found, your vet may prescribe anti-anxiety medications to relax the cat while you work out the problem.  If necessary, seek the help of a second veterinarian and/or a cat behaviorist -- both Tufts' and Cornell's veterinary programs have fee-based help lines for cat issues.