There is a specific kind of despair that comes with finding the third puddle of the week in the same corner of the hall. It usually arrives with a theory attached: the dog is being spiteful, or lazy, or getting back at you for going out. Dogs do not do any of those things. They lack the machinery for a grudge held over hours, and the corner of the hall was chosen for reasons that have nothing to do with you.
Accidents are almost always one of four things: a medical problem, an unfinished house training job, a smell you did not fully remove, or a dog left longer than it can physically hold. Work through them in that order and most cases resolve inside a couple of weeks.
Rule out the medical thing first
This step gets skipped constantly and it is the one that costs the most time when it is wrong. A urinary tract infection, bladder stones, early kidney disease and diabetes all present the same way at home: a house trained animal that suddenly is not.
The pattern to watch for is sudden change. A dog that has been reliable for three years and starts having accidents in a week is a medical case until proven otherwise. So is a dog straining, going little and often, drinking noticeably more than it used to, or leaking while asleep. None of that is trainable. Book the vet, and take a fresh urine sample with you if you can catch one, because it saves a second visit.
Only once that is clear does the behavior work make sense.
Clean it properly, or it happens again in the same spot
This is the single most common reason a house training problem will not close.
A dog's nose is orders of magnitude better than yours. You cannot smell the spot after you have cleaned it. The dog can, easily, and a marked spot is an invitation to mark it again. Worse, most household cleaners are ammonia-based, and ammonia is one of the main components of urine. Cleaning a puddle with a standard spray does not remove the message, it reinforces it.
What works is an enzyme cleaner. Enzymes break down the uric acid crystals that ordinary detergents leave behind, which is the part that keeps smelling for months. An enzyme stain remover is the right tool, and the method matters as much as the product. Soak the area rather than misting it, because urine travels down into carpet backing and underlay and the surface is the smallest part of the problem. Leave it wet for the time on the label, do not scrub, and blot rather than rub. Skip the steam cleaner entirely on urine, because heat sets the protein and makes the stain permanent.
Do the whole area, not the visible mark. If you have a suspicion the dog has been going in more places than you have found, turn the lights off and check with a UV flashlight before you decide the job is done.
Shrink the house while you fix it
House training fails in proportion to how much unsupervised space the animal has. A dog that can drift two rooms away from you will find somewhere quiet to go, and every successful accident makes the next one more likely.
The answer is not confinement as punishment, it is simply less territory for a few weeks. A folding pet fence keeps the dog in the room you are in, which means you catch the pre-pee signals, the circling and the sniffing, in time to get outside. An indoor barrier net does the same job in a doorway or at the bottom of the stairs, and packs away when you have visitors.
For apartments, high floors, or an owner with limited mobility, an indoor grass potty tray gives a small dog a legitimate indoor target instead of a corner it chose itself. Put it as far from the food and bed as the room allows. Treat it as a transitional tool rather than a permanent solution for a dog that can be taken outside, because you eventually have to move the target and that is easier the sooner you do it.
The part that actually does the training
Everything above buys you the conditions. The training itself is short.
Take the dog out on a clock, not on a hunch. First thing, last thing, after every meal, after every nap, after every burst of play. A young puppy needs roughly one hour of holding per month of age, and no dog of any age should be expected to hold it for a full working day.
Pay it outside, immediately. The treat happens outside within three seconds of finishing, not in the kitchen thirty seconds later. Late payment teaches the dog that coming back inside is the thing being rewarded.
Say nothing about accidents. Not a raised voice, not the old nonsense about the nose. All that teaches is that going in front of you is dangerous, which produces a dog that hides to go, which is much harder to fix than where you started.
Older dogs, small dogs and the belly band
Two situations do not respond to training because they are not training problems.
An intact male marking indoors is doing something socially motivated rather than emptying his bladder. It is usually vertical, small in volume, and aimed at furniture legs, bags and anything new in the house. A belly band wrap stops the damage while you address the cause, which is usually neutering, a new animal in the house, or a change he found unsettling. Change the liner every few hours. A wet band against skin causes scalding quickly.
An older dog with genuine incontinence, particularly a spayed female leaking in her sleep, has a hormonal problem with an effective medical treatment. The band manages the laundry. The vet fixes the cause.
Making the outdoor trip easy enough to keep doing
The reason people quietly stop taking the dog out at eleven at night in November is friction. Remove it.
An LED bag dispenser on the lead means the bags and the light are already with you and you are not hunting for a phone flashlight one-handed in the dark. In a yard, a claw scooper with a built-in bag dispenser makes the clean-up a ten-second job, which matters more than it sounds, because a yard that has not been cleared is a yard a dog is reluctant to use.
When to go back to the vet
Go back if the accidents continue after two clean weeks of the routine above, if the dog is straining or crying, if there is blood, if the volume or frequency of drinking has changed, or if an older dog has become confused about doors and routines in general. Canine cognitive dysfunction presents as house training loss surprisingly often, and there are things that help it, but only if someone identifies it.
The cleaners, trays, barriers and clean-up kit are all in home and clean-up.
