Understanding ADUs and JADUs in Santa Cruz County: A Comprehensive Guide

Dax Nollenberger
- Dax Nollenberger

Understanding ADUs and JADUs in Santa Cruz County: A Comprehensive Guide

In the face of a transforming housing landscape and tightening availability, California has embraced Accessory Dwelling Units (ADUs) as a beacon of opportunity and practicality. Bolstered by state laws, cities, and counties have been mandated to open doors to Accessory Dwelling Units (ADUs) and Junior Accessory Dwelling Units (JADUs), offering homeowners new opportunities to maximize their property’s potential. That said, this statewide initiative has led to a plethora of local ordinances, each with its own set of rules that can overwhelm those considering an ADU build.

In Santa Cruz County, the rules can vary depending on the location of your property. The incorporated cities—Santa Cruz, Capitola, Watsonville, and Scotts Valley—each dictate their own ADU regulations. In contrast, the unincorporated areas abide by the Santa Cruz County municipal code. This blog is the first in a series of ADU regulation educations that will address each regulating body in Santa Cruz County. Today, we start with the County itself. 

As a Santa Cruz Realtor eager to educate both myself and my readers through extensive research, I aim to provide a base of knowledge that allows you to take action and tackle your ADU adventure. In this blog, we’ll delve into the nuts and bolts of what an ADU is, explore its potential to alleviate the housing squeeze and navigate the specific regulations you’ll need to understand before adding an ADU to your property.

Dax’s Disclaimer: These regulations are subject to change. While I pride myself on my ability to research and present information, this is not meant to supplement the research and due diligence required by you to build an ADU on a property. Always consult with the County for eligibility requirements. 

What is an ADU?

An Accessory Dwelling Unit (ADU) is an independent dwelling unit with a dedicated exterior entrance that provides complete living facilities for a household… To meet this definition, ADUs must have a full kitchen, including a built-in permanently installed cooking appliance, and a full bath with facilities for sanitation and bathing. Courtesy of Santa Cruz County Code. See the Resource section for a link. 

What is a JADU?

A Junior ADU, or JADU, is a dwelling unit contained within the walls of a proposed or existing dwelling unit, with a dedicated exterior entrance. JADUs can be converted from either habitable space (such as an existing bedroom) or non-habitable space (such as a garage or storage area). JADUs may not be more than 500 square feet in size, including additions of no more than 150 square feet. JADUs must include all of the following facilities: independent provisions for living, sleeping, eating, and cooking (area meeting the definition of an efficiency kitchen), and shared or separate sanitation facilities with the main dwelling unit. Courtesy of Santa Cruz County Code. See the Resource section for a link.


Conversion ADU- The conversion of any portion of a legal accessory structure, or any portion of a single-family dwelling, or any garage, for the purpose of creating an ADU.

ADU Benefits

Now that it is clear what an ADU is, let’s discuss the potential benefits. 

  1. Additional Income: The most obvious of the benefits listed, ADUs can supplement the mortgage, offset living expenses, or even pay for your next vacation!
  2. Increased Property Value: Properties with ADUs are becoming increasingly attractive, particularly for those looking to jump into the market for the first time. While ADUs won’t influence every buyer, they are a nice incentive to encourage buyers to pay more. 
  3. Flexibility and Versatility: Even for those not looking to rent out the space, ADUs provide an opportunity for multi-generational living, a guest house, or even a work-from-home office space. 
  4. Value-Add Investor Opportunity: For those looking to build wealth through real estate, ADUs provide the potential for a significant increase in monthly rental income in addition to increased property value. 
  5. Community Benefit: ADUs increase housing availability for renters, reducing the housing crisis in Santa Cruz County. 

Rules and Restrictions

Number of ADUs

  • Single Family Home: One ADU and one JADU are allowed. 
  • Multi-Family Dwellings: On a parcel with an existing or proposed multi-family dwelling: up to two detached ADUs, which may be attached to each other, and a conversion ADU as long as it’s up to 25% of multifamily units. 

Dax’s Take: While the benefit of two additional structures is great for single-family homes, multi-family received an even larger benefit with the potential to add three additional living spaces to the property. That said, the restrictions listed below limit the number of properties that are eligible for multiple new living spaces. 

ADU Size

  • Minimum: JADU or ADU: 150 sqft. 
  • Maximum unit size, JADU: 500 sqft. 
  • Maximum unit size, ADU:
    • Conversion ADU: No maximum size. 
    • New Construction ADU, Attached: 
      • Parcel size less than 1 acre: 850 square feet (studio or one bedroom), 1,000 square feet (two or more bedrooms), or 50 percent of primary dwelling habitable square footage, whichever is smaller.
      • Parcel size greater than 1 acre: 50 percent of primary dwelling habitable square footage. 
    • New Construction ADU, Detached: 
      • 850 square feet (studio or one bedroom), 1,000 square feet (two or more bedrooms).
      • Parcel size greater than or equal to one acre: 1,200 square feet.
    • According to the County Code, regardless of the notes in this section, an ADU of at least 800 sqft feet shall be allowed.

Dax’s Take: This one is confusing but I’ll do my best to provide some clarity. The last note supersedes any restrictions listed above. That is to say, ADUs of at least 800 sqft are allowed. For attached ADUs, this means you can have a home that is 1200 sqft, limited by the 50% primary sqft feet rule (600 max ADU), but superseded by the last note allowing for an ADU of 800 sqft. 


  • New Construction Setbacks
    • Front setback is subject to the applicable zone district. The side and rear shall be 4 feet (or the applicable zoning district, whichever is less).
      • An 8 ft rear setback is required for any portion of an ADU over 16 feet tall.
    • Minimum separation distance between ADUs and other structures shall be three feet.
    • See County Code for all restrictions and exceptions. 

Dax’s Take: Consult with County officials and building experts/architects to determine what and where you can build.  


  • New construction detached ADUs shall be a maximum of 16 ft. 
  • ADUs built on top of a garage shall be a maximum of 20 feet exterior wall and 24 feet at the roof peak. 
  • Inside the Pleasure Point Combining zone district, ADUs that are built above garages shall be a maximum of 18 feet exterior wall and 22 feet at the roof peak. 

Lot Coverage

  • Parcels with ADU shall meet lot coverage and FAR standards for the applicable zone district, except that JADU and/or ADU square footage up to 800 sq ft may be excluded from Floor Area Ratio (FAR) and lot coverage calculations for both existing and new parcels.
  • Zoning that does not involve a FAR standard includes RA, RR, A, AP, and CA. R-1 with 16k lot minimum.

Dax’s Take: The 800 ft that is excluded becomes an important piece when determining what you can build. Urbanized zones are more likely to already be up to max lot and FAR coverage. This may limit your ability to build multiple ADUs on your property. 


  • JADU have no parking requirements 
  • ADU: one off-street parking space per ADU. 
    • ADU parking may be located in ADU setback areas. 
    • NO additional parking for an ADU shall be required if the ADU is located within one half-mile walking distance of any public transit stop, within a designated historic district, or within one block of a dedicated parking space reserved for publicly available car share vehicles. 
    • For areas with permit on-street parking, permits shall be offered to occupants of the ADU and/or JADU. 
    • Replacement parking- When a garage, carport, or covered parking structure is demolished or converted into an ADU or JADU, no replacement parking is required for the primary dwelling unit. 
    • Special Coastal Zone Parking Requirements- one space is required with no exceptions and replacement parking is required when existing parking is demolished. 
    • LODA, SALSDA, DASDA, and Opal Cliff Dr between 41st and the city of Capitola. 

Dax’s Take: When attempting to maximize your space, parking requirements often put a damper on your plans. That said, the exemption when located within a ½ mile of a public transit space is a critical distinction that opens up your opportunities. To view public transit stops visit: https://www.scmtd.com/en/routes/schedule/map

Other Rules

  • New, detached ADUs must have solar.
  • If the home is on septic, adding ADUs increases septic requirements. Consult with Environmental Health Services regarding feasibility. 
  • ADUs cannot be rented as a short-term rental. In addition, ADUs make the property ineligible for short-term rental permits. 

Owner Residency

  • For JADUs or ADUs not permitted between January 1, 2020, and January 1, 2025: The owner must reside in one of the properties.
  • On properties with ADUs permitted during the five-year period from January 1, 2020, through January 1, 2025, owner occupancy is required only if there is also a JADU on the property.

Dax’s Take: This is a critical fact that will can impact your ADU plans. I loathe this rule and frankly do not understand the reasoning for its implementation in the first place. That said, CA has passed laws, for a period, that allow non-owner occupancy. It seems likely that these new ordinances will eventually be extended given our rental housing shortage. My understanding is that if it was permitted before 2020 and is not owner-occupied, it can not be rented. 

Application Processing

  • Ministerial approval (approves or denies based on predetermined rules)
  • Must get a response within 60 days. 
  • Exceptions to ministerial review: Inside a Coastal Zone or don’t meet the development standards.

Dax’s Take: The goal of ministerial approval is to reduce red tape and improve processing. If your lot and design meet the restrictions above, approval will be granted. 

Permit + Processing Cost 

  • Cost is size dependent. ADUs under 750 sqft are exempt from both impact fees and most building permit review fees. ADUs over 750 sqft will cost you 3X ADUs under 750 sqft. 
  • EX: A new construction detached ADU in Live Oak will cost an estimated $5512 for 749sqft and $17,451 for 750sqft. 
  • County Provide ADU Fee Estimator: https://www.sccoplanning.com/ADU/Planyourfinancing.aspx

Dax’s Take: This is critically important to factor into design. ADUs that are less than 750 sqft are going to save you thousands of dollars. 


In conclusion, understanding the local and state laws can be a vital advantage for a homeowner. Whether you’re a homeowner seeking to enhance your property’s value, a community member interested in addressing housing shortages, or an investor exploring Santa Cruz County opportunities, this guide aims to provide essential insights and practical knowledge when it comes to ADU benefits, requirements, and restrictions in Santa Cruz County. 

If you find yourself intrigued by the possibilities of ADUs and JADUs, or if you have specific questions about how these developments could impact your property and investment plans, don’t hesitate to reach out. As a Santa Cruz Realtor committed to staying at the forefront of real estate trends and regulations, I am here to assist you in exploring these opportunities further. Let’s work together to turn your real estate aspirations into reality. Contact me to start your real estate adventure today. Email me today at [email protected].

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Thanks for reading! 831-227-5847

– Dax


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