[header] How to house train an older dog [title] Learn as much as you can about the dog's background. [step] If you have recently adopted or purchased the dog, call the source and find out as much as you can about the dog's previous habits and upbringing. It is helpful to know if the dog was partially house-trained in the past. 
It is also helpful to know if the dog was confined for long periods of time in a particular environment (exclusively outdoors, on a concrete floor at a shelter, in a kennel, etc. ) as this can cause surface preferences that you may need to overcome.