Direct answer
If your puppy was reliably going outside and suddenly starts having accidents indoors again, don’t assume they’re simply “regressing.” A new change in urination or bowel habits is worth discussing with your veterinarian first, because medical problems can look exactly like a training setback.
Once medical causes have been ruled out, the next step is to look at what kind of accident is actually happening. Not every indoor pee means the puppy has forgotten potty training.
- Look at the context. Urination during greetings, excitement, nervous interactions, or moments of social pressure may be emotion-related rather than a failure to understand where to toilet.
- Look at the pattern. Small amounts of urine in particular locations can be different from a puppy fully emptying their bladder indoors and may call for a different interpretation, including marking behavior.
- Then look at what changed. Feeding times, sleep, supervision, who takes the puppy outside, access to rooms, longer gaps between potty breaks, travel, visitors, or other routine changes can all change the opportunities a puppy has to succeed.
If the problem really is a housetraining setback after medical and context-specific causes have been considered, go back to the basics that were working before: more predictable potty opportunities, closer supervision, immediate reinforcement for toileting in the right place, and temporarily reducing opportunities for mistakes.
What matters most is not to treat every indoor accident as the same problem. A sudden medical change, excitement urination, marking, and a routine-related housetraining lapse may all look like “regression” from across the room, but they need different responses.
If your puppy is straining, urinating very frequently, producing unusually small amounts, showing blood in the urine, having diarrhea or vomiting, drinking noticeably more, is unable to urinate at all, or seems unusually lethargic, contact your veterinarian rather than waiting to see whether more training fixes it.