Yes, the dog is house-trained. It has been taught to go to the bathroom outside and knows to wait until it is let out. The dog understands the rules of the house and follows them consistently. **

There could be several reasons why your dog is not going into the dog house. It's possible that the dog house is too small or uncomfortable for your dog, or it may not feel safe or secure inside. Your dog may also prefer being closer to you or other family members instead of being in the dog house. Additionally, if the dog house is too hot, cold, or lacks proper ventilation, your dog may choose to stay outside instead. **

No, dogs do not need an S-Bahn ticket in most cases. Small dogs that can be carried in a bag or on a leash may travel for free on public transportation in many cities. However, larger dogs may require a reduced fare ticket or a separate ticket depending on the transportation provider's rules. It is always best to check with the specific transportation company for their pet policy before traveling with a dog. **

It is unclear from the information provided whether the dog is house-trained at the family's friends' house. The dog's behavior of urinating on the carpet suggests that it may not be fully house-trained in that particular environment. It is possible that the dog is not used to the new surroundings or may be feeling anxious, leading to accidents inside the house. It would be helpful for the family to monitor the dog's behavior and provide additional training or support as needed. **

There could be several reasons why your dog is not house trained. It could be due to a lack of consistency in the training process, not providing enough opportunities for your dog to go outside to eliminate, medical issues such as urinary tract infections or gastrointestinal problems, or anxiety or stress causing accidents. It's important to identify the underlying cause and address it accordingly to successfully house train your dog. **

To house-train a dog, you will need to establish a routine for feeding, potty breaks, and playtime. Take your dog outside frequently, especially after meals and naps, and praise them when they go potty outside. Use positive reinforcement such as treats and verbal praise to reward good behavior. Be patient and consistent with your training, as it may take some time for your dog to learn. **

To house train a dog, you will need to establish a consistent routine for feeding, walking, and bathroom breaks. Take your dog outside frequently, especially after meals and naps, and praise them when they go to the bathroom outside. Use a designated spot in the yard for them to go to the bathroom, and be patient and consistent with the training process. It's also important to clean up any accidents inside the house with an enzymatic cleaner to remove the scent and discourage repeat accidents. With time and consistency, your dog will learn to go to the bathroom outside and become house trained. **

Yes, you can buy a used dog house. Many people sell their used dog houses when they no longer need them, and you can often find them for sale online through websites like Craigslist or Facebook Marketplace. Buying a used dog house can be a more affordable option than purchasing a new one, and as long as it is in good condition, it can provide a comfortable shelter for your pet. Just be sure to thoroughly inspect the used dog house for any damage or signs of wear before making a purchase. **