Yes, you can build a guest house in your backyard. However, you may need to get zoning approval from your local municipality first. Additionally, you'll need to make sure that the guest house is up to code and meets all of the relevant building codes. Finally, you'll need to make sure that the guest house is insured and that you have liability insurance in case of any accidents.

It depends on your zoning laws and what other permits you may need. You should always consult with your local municipality to find out what is allowed. Some things you'll need to consider before building a guest house in your backyard include: the size of the guest house, the height of the guest house, how it will be connected to utilities, and whether or not it will require a permit. If you're unsure about anything, it's best to consult with a contractor or an architect.