ADU Address Requirements in California: Are they Separate?

Apr 3, 2024

Understanding ADU address requirements in California

When embarking on the construction of an Accessory Dwelling Unit (ADU) in California, particularly in San Diego, homeowners often encounter the nuanced process of obtaining a separate address for their new ADU. The process can vary significantly from one jurisdiction to another.

In San Diego, despite the fact that the city has assigned a new address to your ADU, you must still go in person to the post office and request the new address. The post office will request proof of your building permit, which is shown on the first page of your approved plans.

If not located within the City of San Diego, some cities will assign addresses and coordinate directly with the USPS, while others will not require a new address at all. If you desire a new address, you will be asked to provide your building permit from the city.

Does an ADU need its own separate address?

Yes, in most cases, an ADU will require its own distinct address from the primary home. This is not just a bureaucratic formality; having a separate address for your ADU facilitates the connection of utilities, ensures proper mail delivery, and aids first responders in case of emergencies. It also helps in distinguishing the ADU as a separate living space, which can be particularly important for rental situations or resale purposes.


A separate address for an ADU ensures that utility services can be connected and billed accurately, which is especially important if the ADU is intended for rental purposes or if the homeowner wishes to keep utility payments distinct from those of the primary residence.

Mail Delivery & Rentals

Moreover, a unique address is essential for effective mail delivery. Without a separate address, there could be confusion or delays in mail service, impacting both the occupants of the primary residence and the ADU. It also simplifies the process of renting out the ADU, as a separate address allows for clearer rental agreements and can help in managing tenant utilities and services more efficiently.

Emergency Services

This distinction becomes even more crucial in emergency situations. First responders rely on clear, accurate addresses to locate properties quickly. In the event of a medical, fire, or police emergency, having a separate address for the ADU could potentially save lives by eliminating any ambiguity about the location needing assistance.

How to get an address for an ADU in San Diego

When adding an accessory dwelling unit to your property in San Diego, one crucial step that often catches homeowners by surprise is the process of obtaining a new address for the unit. Unlike most cities in Greater San Diego where this step is handled internally, San Diego requires a bit more legwork from the homeowner, especially when it comes to utilities and postal services.

The Challenge: Connecting Utilities to Your New ADU

A common hurdle for ADU owners in San Diego is setting up utilities, such as solar power. The issue often stems from the new address not being recognized by utility providers like SDG&E, due to a lack of communication between the city and the utility companies. This disconnect can delay essential services for your ADU, as seen in the case of a homeowner waiting two months for solar hookup post-inspection.

The Solution: Certifying Your ADU Address with the USPS

The key to resolving this issue lies with the United States Postal Service (USPS). Although the City of San Diego provides an address during the plan check phase, this address needs to be certified by the USPS to be fully operational and recognized by other entities, including utility providers.

Here’s a step-by-step guide to ensure your ADU’s address is certified in San Diego:

  1. Obtain Proof of Address: Start by securing a document from the city or county on official letterhead, or with the city/county seal, confirming the registered address for your ADU. This serves as proof that your new address is legitimate and recognized by local government.
  2. Provide Photos of the Delivery Location: Take clear photos of where the new mailbox will be installed. Ensure the mailbox is located on the street of the new address and accessible for delivery Monday through Saturday. Also, capture a photo of the main home’s mailbox to demonstrate proximity and practicality.
  3. Submit Mailbox Design: If you’re installing a new mailbox or a slot within an existing mailbox for the ADU, include a picture or schematic of the design. The opening should be at least 1 ¾ inches wide by 11 ½ inches long to comply with USPS standards.

Why Your ADU Address Matters

Ensuring your ADU’s address is recognized by the USPS and subsequently by utility providers like SDG&E is crucial for the smooth operation of your new unit. It’s not just about receiving mail; it’s about fully integrating your ADU into the city’s infrastructure, from utilities to emergency services.

Getting Started on your ADU address process in San Diego

You’ll need an example “Approval Report” that satisfies the requirement for proof of address. From there, you’ll need to gather the necessary photos and visit your local post office to complete the process.

We understand the intricacies of ADU development in San Diego and are committed to making your ADU project as seamless as possible. Request a consultation.

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