It is generally haram to keep a dog as a pet in the house due to its impurity. However, it is permissible to keep a dog for specific purposes such as hunting, guiding, police duties, guarding houses or property, and shepherding cattle and sheep. If a dog is kept for these purposes, it should be kept outside the house, and care should be taken to avoid letting it make vessels and clothes impure.

And Allah knows best.

Sources:

• IslamQA – Keeping Dogs in Islam
• IslamQA – Guard Dogs
• About Islam – Can Muslims Own or Keep Dogs