What should I do with potty accidents 15x a day?

I would like to know the answer to this too.

A lot of answers are really general and they only cover a small portion of options. Most answers are assuming this is the first time a dog is at a new place, & people are assuming the dogs are not going out enough.

What about when it’s a place that the dogs have been to several times before? What about when the dogs get let out every two hours, for at least 20 minutes? They should have completely emptied their bladders by then, but there are plenty of dogs that we watch, that we let out plenty of times, for a long enough duration, yet they still come back in and Pee. ( especially male dogs that mark their territory, we will find upwards of 10 + pee spots all over)

We have cleaned up spots with the enzyme remover and we have sprayed anti-potty spray. They still seem to go everywhere.

Again, I understand it comes with The “territory” of being a pet sitter. But when you’re doing everything you can to let them out enough, and keep the house clean & free of Pee smell, so other dogs don’t go, it gets really confusing on WHY the dogs keep going in the house.