Whether expanding your family’s homestead or looking for rental units to provide long-term income growth, an Accessory Dwelling Unit (ADU) may be the answer.  Better known in the past as granny units, an ADU requires its own kitchen.  ADUs are now allowed by California state law, and all our cities and counties now cooperate to allow more infill housing, subject to some local conditions.  Since 2017, California ADU laws have greatly reduced local permit fees and reviews, simplified building codes, allowing optional separate utilities, and reduced or eliminated additional parking requirements. You can even convert legacy structures on your property to legal dwellings as ADUs.

Here in Cloverdale, my husband Michael Princevalle and I have built three new ADUs within the City of Cloverdale.  As local residents ourselves, our ADUs have been on existing single-family properties we have purchased in town since 2017 to use as rental housing.  I focused more on the designs and landscaping, and Michael focused on site planning, drainage, and irrigation needs.  The Cloverdale planning and building departments have been very cooperative.  We want to share our experience with others who may have a similar interest in building ADUs for additional housing.

Are you eligible to build an ADU?  To start with, you must own an existing residential property (either single or multifamily).  The ADU you develop may be attached to, or detached from, your existing dwelling. The ADU may be new construction or could be converted from a garage or carport.  For details on what is allowed in Cloverdale, see the brochure on the City’s building department at this link: https://www.cloverdale.net/DocumentCenter/View/4341/Accessory-Dwelling-Unit-Brochure

In our situation, our three ADUs were split across 2 single family home properties.  Luckily, many existing homes in Cloverdale have room for adding ADUs on their parcel.

Property #1 was a .25-acre parcel with an existing 4 bedroom home from the 1950s, where we did a garage conversion for the first ADU to create a studio apartment, and then added a standalone 2 bedroom modular/manufactured home on foundation to create the second ADU. Both new units fit within the total 1200 square foot ADU maximum limit for the parcel.  Our result was a 3-unit multi-family property.

Property #2 was a .20-acre parcel with an existing 2-bedroom home from the 1950s.  In this situation we added a separate 1-bedroom manufactured home on foundation to create the second ADU, resulting in a 2-unit property. 

In all cases, the remodeled existing homes and the new ADUs rented favorably at market rates to long-term renters, with anticipated rent payback of ADU construction costs within 5 years.  All units have their own gas, electric, and cable utilities with separate bills for tenants.  We provided dedicated driveways per unit to reduce the impact on street parking.   The two customized manufactured ADU home had a 6-month lead-time from placing order to occupancy, including underground utility extensions.  This 6-month turnaround was remarkable, especially since each home was provided by two different resellers representing different manufacturers.

Our recommendations for successful ADU development:

  1. Consider unit orientations and access to allow privacy for all residents. Consider sound-proofing shared walls between units.
  2. Buy manufactured homes whenever possible to save at least 60% on both time and money compared to onsite construction. Dealers have ADU floorplans to share with the latest building codes. Customizing upgrades on your home order is easy. Your home will arrive with all cabinets, appliances, trims, and window coverings already installed!  Plus, they have their own installation contractors to speed the building process.  As we know, traditional general building contractors in Sonoma County are scarce…busy mostly on replacing homes lost to fires. It is possible to purchase and install a nice, manufactured home between 500 and 1000 square feet for less than $100,000.


American Dream Homes, dealer of manufactured/modular home plans and models, Santa Rosa

Anne Miserlian Baker, ADU savvy Cloverdale Realtor, 707-894-9201

Exchange Bank, good source for home equity lines of credit or short-term loans for homeowners

Cloverdale Planning Department ADUs, Rafael Miranda, rmiranda@ci.cloverdale.ca.us or 707-894-1726

Sonoma County ADU link for parcels outside City limits: https://sonomacounty.ca.gov/PRMD/Regulations/Housing/Housing-Types/Accessory-Units-and-Junior-Units/Accessory-Dwelling-Units/

Nancy Lloyd, for questions regarding this article, nancyalamo@yahoo.com