Building an ADU in Santa Cruz County

Santa Cruz County ADU Project

Building an Accessory Dwelling Unit in Santa Cruz County: A Comprehensive Guide

With the rising demand for affordable housing options, Accessory Dwelling Units (ADUs) – also known as “in-law units” or “granny units” – have become an increasingly popular solution, particularly in Santa Cruz County. By adding an ADU to your property, you can not only enhance your living space but also significantly increase your property’s value. This comprehensive guide will walk you through the key considerations and steps involved in designing and building an ADU in Santa Cruz County.

1. Introduction to ADUs

An Accessory Dwelling Unit (ADU) is an additional, self-contained housing unit that resides on the same lot as your primary residence. As per the minimum requirements, an ADU should include a kitchen, a bathroom, and a sleeping area. The kitchen should be equipped with a countertop, cooking appliances, a space for refrigeration, and a sink. The size of an ADU can vary, ranging from as small as 150 square feet to as large as 1,200 square feet, depending on specific zoning and individual needs.

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2. Why Build an ADU?

There are numerous reasons why homeowners choose to build an ADU. For some, it provides a separate living space for family members, a home office, or a rental unit. With the steep rise in rental prices, ADUs have become an attractive option for homeowners looking to generate extra income.

Moreover, ADUs also offer a solution to the housing crisis in Santa Cruz County, where home values and rental prices are significantly higher than the national average. By adding an ADU to your property, you not only increase your property’s value but also contribute to alleviating the local housing shortage.

3. Types of ADUs

ADUs can come in various forms, each offering unique benefits depending on your available space and specific needs:

    • Conversion ADUs: These units are converted from existing structures, such as garages or basements.
    • Attached ADUs: Attached ADUs are like an addition to the main house but are completely separate units.
    • Detached ADUs: If you have a large lot, a detached ADU may be the best option for you. These are stand-alone structures that offer more privacy.
    • Junior ADUs (JADUs): These are smaller units, less than 500 square feet, that can share a bathroom with the main property.

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4. Santa Cruz County ADU Permitting Requirements

Building an ADU in Santa Cruz County requires a building permit, along with architectural drawings, energy calculations, and green building calculations. However, recent laws enacted in California have made the process of building ADUs simpler and more straightforward.

For instance, you can now build an ADU that’s at least 800 square feet while also building a smaller JADU attached to your primary property, regardless of your lot size. Moreover, outside the Coastal Zone, no parking is required for an ADU, and parking spaces removed to accommodate an ADU need not be replaced.

5. Designing your ADU

When designing your ADU, it’s important to consider how it will blend with your existing home. The design should fit in with the style and look of the surrounding property and neighborhood to maintain property values and keep neighbors happy.

You should also consider the level of privacy you want for your ADU. This will largely depend on whether you plan to rent out the ADU or use it for family members.

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6. Maximizing Space for your ADU

Maximizing the space in your ADU is crucial, especially if it’s on the smaller side. Here are some tips to make the most of your space:

  • Use vertical space wisely with shelving and hooks.
  • Utilize under-stair spaces or spare nooks for extra storage.
  • Consider multi-purpose furniture, such as beds that can be folded or rolled out of the way.
  • In bathrooms, use plain glass shower doors instead of curtains to create an illusion of a bigger interior.
  • Opt for smaller appliances in the kitchen that suit your available space.

7. ADU Construction Costs

The cost of building an ADU can vary widely, depending on its type, size, design, and the specific requirements of your property. A garage conversion is usually the least expensive option, while a custom, standalone ADU is more costly.

8. Financing Your ADU

There are various ways to finance the construction of an ADU. You can use your savings, take out a loan, or even use the potential rental income from the ADU to cover the costs. It’s important to talk with your bank or mortgage lender about your options to find the best solution for your situation.

9. The ADU Building Process

The process of building an ADU involves several key steps, from initial planning and design to obtaining permits and construction.

  • Planning and Design: The first step is to plan your ADU and create a design that meets your needs and complies with local regulations.
  • Permitting: Once your design is finalized, you’ll need to obtain the necessary permits from your local planning department.
  • Construction: After your permits are approved, you can begin construction. This stage involves site work, building construction, and inspections.

10. Working with a Design-Build Contracting Firm

Working with a professional design-build remodeling firm can make the process of building an ADU much smoother and less stressful. These firms handle all aspects of the project, from design and permitting to construction, which can save you time and help ensure a successful outcome.


Building an ADU on your property in Santa Cruz County is a significant investment but one that can provide numerous benefits. Whether you’re looking to create more living space, house family members, or generate rental income, an ADU can be an excellent solution. With careful planning, design, and construction, you can create a beautiful, functional ADU that enhances your property and meets your specific needs.

Note: This guide is intended to provide a general overview of the process of building an ADU in Santa Cruz County. Always consult with a professional and check local regulations before starting your project.

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Seb Frey helps long-time Bay Area homeowners make their next move easily the next one yet. If you're looking for a minimum of hassle, maximum net cash on sale, and certain results, contact Seb today.