The Sussex Spaniel is more comfortable being an outside dog than an indoor dog. You can have one as a family pet, but it does have issues with house training. Many people quickly realize that house training a Sussex Spaniel will take patience and time. Even after the dog seems trained, it can still have occasional accidents due to temperamental stress or pure obstinacy. The time to start house training your dog, is the minute you bring it home.
You can house train a Sussex Spaniel by crate training it. Just do not leave it alone for too long in a crate. It has a need for companionship and can suffer separation anxiety. It also needs a good deal of exercise. This is not a dog that can spend the entire day in a crate. As a puppy, it might not be as hard for it to remain in the crate until it is time to go, but as an older dog this would be very hard on the dog.
You will have to confine the dog to areas that are prepared for it, while you are house training. That means that you can't trust this dog to walk around your home without messing if it has not been house broken yet. Always keep it confined to areas that are safe for it, whether it is the outdoors or an area covered in newspaper.
You do want to encourage the dog to go outside, and not in the house. You will want to avoid giving it the opportunity to soil your house because once this is done; it will be even easier for it to do the second time around. This is a habit that will be hard to break if it becomes entrenched. So, better to avoid it all together than to try to stop it after it occurs.
Understand that this dog is never 100% house broken. It will soil the house to make a point if you leave it too long alone or it is in a stubborn mood. If you get the dog obedience training, you can start to establish some firm guidelines for it so that it knows what is acceptable behavior and what is not acceptable. This and further socialization within your family unit can help it to be more agreeable and more compliant with the house rules.
This dog requires an owner with a lot of patience that is home most of the day. The dog does need to be supervised; otherwise it can take to destructive chewing, annoyance barking or howling, and house soiling. Once you have established a good home routine and some respect between the dog and yourself, you can find it makes a great housedog. Just don't be too certain that any good behavior it exhibits is a product of training as it is of its own good will. As soon as the dog is upset, the good will may be out the window and the training may be gone with it too.