Accessory Dwelling Unit

© Santa Cruz Green Builders, Inc. 2011

Santa Cruz Green Builders, Inc.

3727 Cherryvale Ave, Soquel, CA 95073   PHONE:831-566-4485  FAX: 831-426-0439   LIC 915349

What is an ADU?

An ADU is an additional, self contained housing unit that is secondary to the main residence. ADUs are sometimes referred to as “Granny Units” or “Mother-In-Law units” since many ADUs were initially constructed to provide for family members. They can take many forms. In some cases, an ADU can be attached as an addition to the house, or as a second story over a  garage. The garage itself may be converted to an ADU or the the ADU may occupy a basement. An ADU can be a section of the main house that has been separated from the main living space, and an ADU can be a stand-alone unit like a small house or cottage. The City only requires that an ADU have a kitchen, bathroom, and place to sleep.

How is an ADU different than a duplex?

An ADU is limited in size and is smaller then the main residence, and the owner must reside in either the ADU or the main house.

Why would I want to build an ADU?

An ADU can provide a separate living space for family, a home office, or a rental, among many other uses. Many people in the city have a hard time making their mortgage due to the high cost of living in Santa Cruz.  Converting a garage or building a new ADU, and then renting it, is one way to make added income while adding value to your property at the same time.

Here is an example of how an ADU can make you money:

You have a garage in the back of your property with alley access that doesn’t get much use. You have us come out to give a bid for converting the garage into an ADU. We agree to build the ADU for $75,000. You get a loan from a bank for this amount with a monthly payment of $300. We build the ADU and then you rent it for $1,000 per month. After considering the small increase in property tax and insurance, you have a net gain of $650 per month!

At the same time, your property value has risen by $75,000.

How large can my ADU be?

If your lot is 5,000-7,499 square feet, you can build up to 500 square feet.

If your lot is 7,500-10,000 square feet, you can build up to 640 square feet.

If your lot is 10,001 square feet or larger, you can build up to 800 square feet.

How do I find out the size of my lot?

Visit the County Assessor’s Office at

or call the City Planning Department at: 831.420.5100

How much will it cost?

The cost to build an ADU varies widely. A garage conversion can be relatively cheap, while a custom, stand alone, ADU is more expensive. Here is a breakdown of some basic costs.

    City, utility and architectural fees:

    $6,000-8,000 for Planning and Building Dept. fees

    $5,000-7,000 for water, sewer and fire sprinkler connection

    $1,000-3,000 for PG&E hookup and panel upgrade

    $3,000-30,000 for plans ( If the pre approved city plans are used, they will just need minor

                                            revisions and a site plan. If you want custom plans, they could be very

                                            expensive depending on the architect.)

    Building Costs:

    $30,000-100,000 for garage conversions

    $100,000-300,000 for stand alone units

*A note on costs

If you have a tight budget, a garage conversion is the most affordable way to build an ADU and it has the best return on investment if used as a rental. If this is not a possibility, costs can still be kept to a minimum by using one of the City’s pre approved ADU plans. These simple, yet functional ADU plans, can significantly reduce the cost of building.

How long will it take to build?

From the start of the design phase to completion of the ADU, projects usually take about one year. It may take more or less time depending on the complexity of the project and the time of year the process is begun. The actual construction period usually ranges from 4-8 months.

How can I finance building an ADU?

There are many ways that people finance constructions costs. We recommend talking with your current mortgage lender about credit available to you. We’re currently working with the Santa Cruz Community Credit Union to make ADU Construction Loans widely available in the community. Please visit our FINANCE section to learn more

Who can live in the ADU?

Anyone can live in your ADU. Or you can use it as an office.

Can I rent the ADU?


How much can I rent the ADU for?

According to the latest report by the Housing Authority of Santa Cruz County- a studio apartment rents for around $941, and a one bedroom for $1183. 

The University of Santa Cruz Housing Services latest statistics have studio apartments renting from $670 -$1200, and one bedroom units renting from $975 - $1500.  The actual rental cost for your unit will vary.

I don’t live in the City of Santa Cruz.

The information on this page is for residents within the City of Santa Cruz only. If you live outside the city limits and are interested in building an ADU, call us about the guidelines specific to your property location. The County of Santa Cruz has a “secondary unit” plan for building ADUs that could work for you.

Can I see an ADU that Santa Cruz Green Builders has built?

Yes. Call or email us, and we will arrange for a visit.  CONTACT

Where should I start?

The first step is to see if you can build an ADU on your property.

Visit our Do I Qualify page to see if an ADU is right for you.

Then the next step is to visit the County of Santa Cruz Planning Department to see if there are any special restrictions that would keep you from building- be sure to have your property address and/or APN# with you. At this point you can also call us and we can do this step for you. We are also happy to come out to your property to look at your lot configuration, setbacks, and other buildings, to see if your lot can accommodate an ADU.

Once your property is deemed acceptable for an ADU, it is time to find a design. You can use one of the City’s pre approved ADU designs or you can start from scratch and create your own design. We can perform this service or you may choose another architect. We also have architects whom we recommend. Regardless of who you use, it is important that the property owner, builder and architect all work together on the design. This ensures an efficient building process that is kept on budget and results in a much better finish product.

The next step is to find a builder. And that is where we come in!

How do I get in touch with Santa Cruz Green Builders?

Call us at 566-4485 or send an email to


FAQ- Frequently Asked Questions about ADU’s

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