An accessory dwelling unit — a backyard cottage, garage conversion, or in-law unit — can turn one property into two income streams. But Santa Cruz has specific rules about who can live in an ADU and how you're allowed to rent it out.
ADUs have become one of the fastest-growing ways Santa Cruz property owners add rental income, thanks to relaxed state construction rules. But once it's built, the rental rules are stricter than owners expect — especially around short-term rentals. Here's the current picture for both the City and County of Santa Cruz.
Table of Contents
- What Counts as an ADU vs. a JADU
- Size Limits
- How Many ADUs Can You Have
- Owner-Occupancy Rules
- Can You Rent Your ADU Long-Term?
- Can You Rent Your ADU on Airbnb?
- Parking Requirements
- Permit Process
- Should You Add an ADU to Your Rental Property?
Disclaimer: This article is for informational purposes only and should not be considered a substitute for professional legal advice. ADU rules differ between the City of Santa Cruz and Santa Cruz County — confirm your specific parcel's zoning and requirements with the relevant planning department before building or renting.
What Counts as an ADU vs. a JADU
An ADU (accessory dwelling unit) is a separate, independent dwelling with its own kitchen and bathroom — attached, detached, or converted from existing space like a garage. A JADU (junior ADU) is smaller and must be built entirely within the walls of the existing single-family home, capped at 500 square feet.
The distinction matters because JADUs come with an owner-occupancy requirement that regular ADUs don't.
Size Limits
Rules differ slightly between city and county, but the general framework is similar:
| ADU type | City of Santa Cruz | Santa Cruz County |
|---|
| JADU | Max 500 sq ft | Min 150 / Max 500 sq ft |
| Detached, new construction (studio/1BR) | Up to 800 sq ft (exempt) | 850 sq ft |
| Detached, new construction (2+ BR) | — | 1,000 sq ft |
| Conversion ADU | Any size (based on existing structure) | Min 150 sq ft, no max |
| Attached, new construction | 50% of primary home's habitable area, or 850–1,000 sq ft | Same standard, 850–1,000 sq ft |
State law guarantees that at least an 800-square-foot ADU must be allowed regardless of local restrictions (Santa Cruz County CDI, City of Santa Cruz).
How Many ADUs Can You Have
On a typical single-family lot in the county, you could potentially have up to four units total on top of your primary home: one standard ADU, one conversion ADU, one JADU, and one small detached ADU (800 sq ft or less) under state law. Multi-family lots have their own caps — up to 8 detached ADUs on an existing multifamily property, capped at the number of existing units.
Owner-Occupancy Rules
This is where a lot of owners get confused:
- Regular ADUs: no owner-occupancy requirement. You can build an ADU and rent out either the ADU or the main house (or both) without living on the property yourself.
- JADUs: owner-occupancy is required. The owner must live in either the JADU or the primary home, and must record a land-use agreement confirming it. A JADU also can't be sold separately from the main house.
Can You Rent Your ADU Long-Term?
Yes — this is exactly what ADUs are designed for. Both the city and county treat ADUs as long-term housing, and neither requires the owner to live on-site to rent one out long-term (aside from the JADU exception above).
Can You Rent Your ADU on Airbnb?
No — this is the rule that catches the most owners off guard. Short-term rental of an ADU or JADU is explicitly prohibited by both the City and County of Santa Cruz:
- City: Single-family properties with an ADU or JADU are not eligible for the Short-Term Vacation Rental Program at all — for either unit. Multi-family properties with an ADU may qualify only if the owner lives on-site and the short-term rental isn't the ADU itself.
- County: Short-term rentals are banned outright on any property with an ADU or JADU, full stop, under the county's Short-Term Rental Ordinance.
If your income plan for an ADU depends on Airbnb-style bookings, Santa Cruz isn't the market for it — plan for a long-term tenant instead.
Parking Requirements
- Outside the Coastal Zone: No parking required for an ADU in the City of Santa Cruz. Removing existing parking to build the ADU doesn't require replacement.
- Inside the Coastal Zone: One off-street parking space is required, with location-specific standards — check the city's “ADU Parking Required” GIS layer for your parcel.
- County conversion ADUs and JADUs: No parking required.
- County new-construction ADUs: Generally one space required, with exceptions near transit or in historic districts — except within designated coastal areas (LODA, SALSDA, DASDA), where one space is always required with no exceptions.
Permit Process
Most ADUs only need a building permit — no public hearing, no discretionary review, and building permits can't be appealed. You will need:
- Architectural drawings, energy calculations, and green building calculations
- A separate address for the ADU (there's an hourly addressing fee)
- A Coastal Permit if your parcel is in the Coastal Zone or Coastal Appeal Zone
If you have an ADU that was built without permits before January 1, 2020, California's AB 2533 program offers a streamlined path to legalize it — worth checking before you assume a rental is off the table.
Should You Add an ADU to Your Rental Property?
An ADU can meaningfully increase what a Santa Cruz property earns — but only as a long-term rental, and only once it's properly permitted, addressed, and parked correctly. Skipping any of those steps can delay renting it out for months.
If you're weighing whether an ADU pencils out for your property, or you already have one and want it professionally managed and leased, reach out to Andren Homes — we manage both primary homes and ADUs across Santa Cruz County.
Sources: Santa Cruz County — ADU Basic Requirements, City of Santa Cruz — Accessory Dwelling Units