House training
Why is my house trained dog suddenly having accidents?
Last updated 23 September 2026 · How we write and check this
Short answer
A sudden change in a previously reliable dog is most often linked to a stressor, a new pet, a move, a change in schedule, or increased water intake, though it can also signal a medical issue such as a urinary tract infection. Because the two causes look similar from the outside, a vet check is the sensible first step before assuming it is purely behavioral.
Ruling out the physical cause first
Frequent small accidents, straining, or a dog asking to go out far more often than usual point more toward a physical cause than a behavioral one, and a simple urine test can usually confirm or rule out an infection within a day. Starting with retraining before checking for a medical cause can waste weeks addressing a problem the dog physically cannot control.
If the vet check comes back clear
Once a physical cause is ruled out, look for recent changes: a new pet, a shift in your work hours, a move, or even a change in furniture layout can all unsettle a previously confident dog enough to cause accidents. Returning to a tighter schedule for 1 to 2 weeks, alongside identifying and easing the specific stressor, usually restores the previous reliability.
Key takeaways
- Sudden accidents in a previously reliable dog can stem from stress or from a physical cause like infection.
- A vet check is the sensible first step, since the two causes can look identical from the outside.
- Once medical causes are ruled out, identifying a recent household change usually points to the trigger.