Is "Housebroken" a dirty word at your house? Is your dog truly housebroken? He never soils the house except in the case of illness or extreme youth (under 16 weeks)? The fastest, most simple way to housebreak a dog is with a crate. It's natural! You are providing a den for a den animal. Prior to dogs being domesticated, the mom dog took her pups out of the den on a regular basis. Predictability and routine is the key.
It is a big mistake to give your young dog (under one year) the run of too many rooms too soon. A puppy is easily distracted, and suddenly there is an accident.
Poor early training has been the downfall of many a pup. Someone else whelped and raised your puppy, and what happened before you got our puppy may have taught him to be dirty or just not to care. The sooner a puppy begins learning good habits, the easier it is on everyone.
Some owners unintentionally compound poor early training by leaving the pup in a room with papers. If it is an isolated area, the laundry room or the basement, it is probably cleaned infrequently. The puppy gets the message that it is okay to soil the house. If it weren't OK, why would you leave the mess there?
A mom dog wouldn't leave potty mess in the den, and you shouldn't either. The best thing to do for your puppy, and for yourself, is to clean up quickly. You will be teaching that potty mess is unacceptable. It is certainly more desirable and more effective than yelling, hitting, or threatening the puppy.
Eating habits, too, support good canine housetraining. It is ill-advised to leave food available for long periods of time. Besides reinforcing aggression and other undesirable behaviours, constant eating and drinking means constant elimination.
The quality of food is also extremely important. Premium, professional diets are formulated to be 80 to 90% digestible. Feeding less - reduces stool volume.