Are you dealing with a dog who was trained and is now having accidents, or a dog that has always urinated in the house? You need to handle them quite differently. If the dog was trained but is now urinating in the house, it may be a medical problem. You need to have him examined and have his urine checked. If he is geratric he may have lost bladder control, if he is arthritic he may have trouble making it outside (if you have steps he may even be afraid to go out).
If the dog has never learned to urinate outside, you need to handle the situation differently. Use positive conditioning methods to let him know going "outside" is the correct thing and eliminate the odors in the house so the dog does not think that he should be using the house for his toilet.
It can be done, though. It is not easy but definitely worth your efforts.