Have you ever been caught by surprise one day when your reliably housetrained pet suddenly has an accident? I know it's happened to me, and to a lot of other pet owners, too. Our pets who haven't had an accident in years, suddenly starts to have accidents - and semi-regularly, too. Pets don't do it to "be bad" or to "get revenge" on us for something we did (or didn't do); there is generally an underlying cause for the accident. Here are some common reasons why dogs or cats may start to have accidents in the house.
Some medical conditions can cause pets to drink and urinate more. Examples include canine diabetes (or feline diabetes), Cushings Disease in dogs, and liver disease. Pets who are ill may not be able to hold their bladder for as long as they used to and will need to be let out more often.
Treating the underlying illness can provide some relief from the symptoms.
Sometimes it's the medication itself that's used to treat an illness that can cause side effects in pets, like the need to drink and/or urinate more. The more the pet drinks, the more he'll urinate. Once again he may not be able to 'hold it' all day, or may lose control on his way to the door.
Talk to your veterinarian. Ask if the dosage can be adjusted (so long as it's still effective), or inquire about the possibility of trying a different medication. Not all pets react in the same way to a certain medication; they may do better on another one.
Pets who are in pain may be less willing to move around. Something as simple as climbing into a litter box or getting to the door may be difficult - and slower, too, which could result in an accident before they can make it where they're going.
Deal with any underlying pain issues. Many types of supplements and medications are available to help pets with joint pain. Once the pain is gone, or at least lessened, pets will be better able to come get you when they want to go out, as well as make it to the door or litter box.
Pain and mobility issues often go hand-in-hand. Assuming the underlying pain has been addressed, mobility should be easier for the pet. However, decreased mobility isn't always about pain - neurological issues, disc disease, and other medical conditions can make it hard for pets to get around. Pets may not be able to make it outside or to the litter box in time... or they may even soil their bedding if moving around is too difficult without help.
Address the underlying cause of the mobility problems if that's possible. Otherwise, there are things pet owners can do to help their pets get around.
Dogs: Put down non-skid rugs or mats for traction on slippery floors. Use carpet stair treads for staircases that aren't carpeted. Build or buy a ramp to make it easier for dogs to get up and down stairs or into the car. Dogs with hind end or hind leg weakness can be helped with the use of a rear-lift harness (also called rehabilitation harness or a mobility harness or sling). Ultimately, you may just need to help your dog out for a bathroom break more often.
Cats: Move your cat's litter box to an area where she can easily get to, without having to climb stairs. Don't put the litter box near her food, though; cats don't like to eliminate near where they eat. A litter box with lower sides can also be helpful for cats with mobility problems. Many litter pans for dogs have lower sides.
Pets can lose control of their bladders and/or bowels due to various health problems, injury, hormonal imbalances, medication, or old age.
Consult with your veterinarian to see if an underlying cause for the incontinence can be determined. If so, treating the cause of the incontinence may resolve the issue. Sometimes there are medications that can help to stop regular accidents.
If the incontinence cannot be resolved, then clean-up can be made easier by layering your pet's bedding. Wrap dog or cat beds in a waterproof cover (some beds come with one). Put down puppy pads next, which will absorb any liquids. Then pile layers of bedding on top. That way your pet can still be comfy and it's a relatively easy clean-up to pull all the bedding off and throw it in the washer. Soiled puppy pads can be discarded in the trash, or buy the reusable type and throw them in the laundry with the rest of the bedding.
A pet's skin can become severely irritated if it's in prolonged contact with urine. If your pet has messed itself, wash or wipe him off thoroughly and promptly. Pet diapers are also available; if using them, be sure to check them regularly so that your pet doesn't stay in a soiled diaper for long. Some people use baby diapers and simply cut out a hole for the dog's tail.
Occasionally pets may be afraid of certain things, noises, sights or locations. Some pets also get anxious if anything in their environment changes. Even if the pet has been using the same spot for bathroom breaks in the past, more recent experiences may be causing them anxiety. For example, if a cat was using its litter box at the same time a loud, scary noise happened to occur, it might associate the location of its litter box with that loud, scary noise.
Anxiety can also be caused by pain. Kitty might find it too difficult to get into her litter box if it's too high, so instead she eliminates outside of it.
If you know what is causing the fear or anxiety, resolving the underlying cause (or desensitizing your pet to it) will work best for the long-term. If you don't know the reason then it's going to be a bit of trial & error to find something that works for your pet.
Dogs: If your dog is showing reluctance to use a certain area of the yard, then pick a new one. You can encourage him with lots of praise and treats, and perhaps even plant something interesting in the spot that will draw him over.
Cats: Moving the litter box somewhere quiet and private may help. A litter box with lower sides can also help cats who have pain or mobility issues. Many dog litter pans have a lower entry.
Also, if you've recently changed the type of litter you use in the box, consider changing it back. Cats can be finicky and may not want to use the new type of litter.
Pets can experience cognitive decline, or senility, just like people can. They may not remember that they're supposed to go to the bathroom outside or in the litter box, and might simply go when the urge hits them.
Reinforce housetraining. Be consistent and positive. A reminder may be all that's needed to get your pet back on track. Sometimes, though, pets cannot be re-trained because they simply can't remember what they've been taught.
Dogs: Make it easier on dogs by letting them out more often. You might also consider laying down training / incontinence pads down in areas where frequent accidents occur, just to make clean-up easier.
Cats: Place the litter box in a location where she regularly passes by. Cats might also find it easier to have multiple litter boxes in various locations throughout the house.
An aging body will eventually start to wear out. Senior pets often cannot hold their bladder or bowels as long as they used to. Sometimes incontinence can occur.
Dogs: Let the dog out for more bathroom breaks. 'Re-train' yourself to let the dog out more often (set an alarm if you have to). Try to catch him before he becomes desperate to go and can't make it to the door in time. Otherwise, check out the suggestions in the 'Incontinence' and 'Dementia' sections for more things you can try.
Cats: Clean the litter box more frequently. If the cat is eliminating more frequently, that means the litter box gets dirtier, faster. Many cats won't use a dirty litter box.
There is no good reason to ever punish a pet for an accident. Addressing the underlying cause of the accidents can help to resolve them. Unfortunately, not everything can be fixed. Lifestyle changes like moving litter boxes, building ramps for dogs, letting dogs out more often, and so forth can help to some extent... but the reality is that accidents are still likely to happen. It's up to us to figure out a way to help our pets as best we can - while trying to stay sane as we deal with cleaning up! A spot cleaning machine can make clean-ups so much easier, especially if accidents happen frequently.