You will need a permit for your ADU in California. The exact type of permit will depend on the rules in the county where you are living and intend to build the ADU. At a minimum, your unit is going to need a building permit. If you plan to put the ADU in yourself, then you must go to the county and get a permit. If you are hiring a builder to help, then they will often get the building permits in line. In some areas, you will need to get other permits as well. This can include an encroachment permit, grading permit, and site review. All property owners, before building the ADU, will need to sign and submit the Accessory Dwelling Unit Rules and Performance Standards along with the building permit. When you are looking at contractors to help you figure out the best way to get started with your ADU, you can ask them whether they get the necessary permits and how they can help you with this step. There may be expenses involved with securing permits that you may need to borrow money for. You may be hesitant to take out a loan for the entire project just to cover permit costs. Taking out a small personal loan to cover permit costs can be a smart idea. If you are granted permits, you can take out a second personal loan to cover building expenses. You may even be able to pay off the first personal loan with the funds from the second personal loan. This way you only have one monthly payment to manage.