A sudden change in a reliable older dog is usually a sign of something new rather than bad behavior. The common causes are a urinary infection, increased thirst from kidney or hormonal disease, leaking from weaker bladder control, sore joints that slow the trip outside, and early cognitive change. A vet visit with a urine sample sorts out most.
Start by describing the accidents precisely
Vets ask a set of questions that point toward one cause or another. Having the answers ready makes the appointment far more productive.
Is it urine, stool, or both? Urine accidents point toward the bladder, kidneys, or hormones. Stool accidents point toward the gut or mobility. Both together raise the odds of cognitive change or a dog who simply cannot get out in time.
Does the dog seem to know it happened? A dog who squats deliberately in the hallway is different from one who wakes up in a wet bed without noticing.
When does it happen? Overnight accidents, accidents within minutes of coming inside, and accidents while you are out each suggest different things.
Has drinking changed? Measure the water bowl for two or three days. A clear jump in intake is one of the most useful clues there is.
Note anything else that has shifted in the past month or two: appetite, weight, energy, coat, how readily the dog climbs into the car, whether it still greets you at the door. Owners often dismiss these as ordinary aging, but together they help a vet decide whether to start with bloodwork, an orthopedic exam, or a behavior history. A phone video of the dog getting up from its bed or squatting in the yard can show a stiffness or a straining posture that is hard to describe in words.
The likely causes, side by side
Several can overlap. An arthritic senior with a mild infection may have accidents for both reasons at once.
The Merck Veterinary Manual's owner section on kidney and urinary tract disorders of dogs is a useful map of the conditions vets consider and how they are investigated.
Why age nine is a common turning point
For many medium and large dogs, nine is well into the senior years. The kidneys slowly lose some of their reserve in many dogs, hormonal disorders become more common, and joint wear begins to change how dogs move. Small breeds may reach this stage later and giant breeds earlier, but the pattern is similar.
Senior screening bloodwork and a urinalysis once or twice a year catch many of these changes before accidents start. If your dog has not had a senior panel, this is a good moment to ask for one. Medication is another factor at this age. Some drugs commonly prescribed to older dogs, including certain steroids and diuretics, raise thirst and urine output as a side effect, so mention every prescription when you call.
Changes that help while you wait for answers
Make the trip outside easier. Shorter paths to the door, a ramp over back steps, rugs on slippery floors, and more frequent breaks, including a last one right before bed, take pressure off a dog who is uncomfortable or slow.
Do not restrict water to reduce accidents. Dogs drinking more usually need that water, and cutting it back can be harmful, particularly with kidney disease.
Clean accidents with an enzymatic cleaner rather than an ammonia-based product. Lingering odor can draw a dog back to the same spot. Puppy pads or a washable mat near the door can buy time for a dog who cannot always make it outside, without undoing years of training.
Skip scolding. A dog who is ill or confused cannot connect the correction to the accident, and stress can make things worse.
Check with your vet before starting any supplement while the cause is still unknown. A new product can complicate the urine results the vet is relying on.
If the answer is a urinary infection
Infections are common in older dogs and usually respond well to the right antibiotic, chosen with the help of a culture. Once the vet confirms the infection has cleared, attention turns to keeping things steady: water, frequent bathroom access, and regular rechecks for dogs who have had more than one infection.
Some owners include a cranberry product in that routine. It is optional, and the evidence for it in dogs is modest. Super Snouts Urinary Support lists cranberry and wild berry as its actives and gives a weight-banded scoop chart on the product page, from one scoop for dogs up to 25 pounds up to four scoops past 100, with twice-daily use for two weeks and then twice weekly. It has no bearing on incontinence, arthritis, or cognitive change, and it does not list a cranberry amount per scoop.
If the cause turns out to be kidney disease, diabetes, or a hormonal disorder, the treatment plan will come from your vet, and supplements should be cleared with them first.
Senior accident questions
Should I go back to basic house-training?
Refresher routines help, but only after a vet has looked for medical causes. Retraining a dog with an infection or kidney disease will not fix the accidents.
Can doggy diapers or belly bands help?
They are useful for managing leaks while you work on a cause. Change them often and keep the skin clean and dry to avoid irritation.
Is it normal for older dogs to drink more?
A modest change with weather or activity is normal. A steady, clear increase is not, and it deserves bloodwork and a urine test.
My dog has accidents only at night. What does that suggest?
Night accidents can point to incontinence during deep sleep, increased thirst, or a dog who cannot wait until morning. A late last outing and a vet check are good first steps.
Could anxiety be the cause?
New stresses, such as a move or a new pet, can trigger accidents at any age. In a senior, rule out medical causes first.
Related reading: Sundowning in Senior Dogs: Why Confusion Peaks After Dark; Cognitive Decline in Senior Dogs: Early Signs and Support; How Much Water Should a Dog Drink a Day?