Dachshunds are not stupid and they are not incontinent. They are small, so accidents are easy to miss until they are a habit; they dislike cold and rain, so they will hold on at the back door and then go inside; and they do not see the point of your rules unless the rules are perfectly consistent.
Treat house-training as a management problem for the first few months. Prevent mistakes rather than correcting them, and reward every single success lavishly and immediately, outdoors, on the spot.
The method
Take the puppy out on a schedule — after waking, after eating, after play, and every hour or two in between — to the same spot, and pay hard with food the instant it performs. Supervise every minute indoors or use a crate or pen, since a dog that never gets the chance to make a mistake learns faster.
If you catch an accident happening, interrupt calmly and carry the dog outside. Never punish after the fact; a dachshund that learns you are unpredictable when angry will start hiding to toilet, which is much harder to fix. Clean accidents with an enzymatic cleaner so no scent marker remains.
Weather and older dogs
Many dachshunds toilet-train faster if you build a covered or sheltered spot and go out with them in bad weather rather than sending them alone. A dog that associates the garden with a miserable soaking will always lobby to come back in.
Regression in an adult dachshund — new accidents after months of reliability — warrants a vet check for a urinary infection or, in an older dog, a back or cognitive problem, before you assume it is behavioural.
