Frequently Asked Questions

The following units are allowed per California Government Code CHAPTER 13 for Accessory Dwelling Units [66310 - 66342], and JADUs.

On a Single-Family Lot

A property with an existing or proposed single-family home may be eligible for the following:

1. One ADU made through a conversion (Government Code 66323 Unit)
2. One Junior ADU (JADU) (Government Code 66323 Unit)
3. One new construction detached ADU (Government Code 66323 Unit)
4. One ADU created using Windsor’s Zoning Code Standards (Government Code 66314 Unit)

The following additional standards apply to the units listed above:

1. One ADU Conversion (Gov. Code 66323 Unit)
   • Must be from existing space
   • ADU must be a fully converted unit and cannot add additional space to an existing structure, except the unit may be expanded 150 sq. ft. from the existing structure for ingress and egress
   • ADU can be within setbacks if the existing structure being converted is within the setback
2. One JADU (Gov. Code 66323 Unit)
   • Can only be created from within an existing or proposed dwelling
   • JADU is 500 sq. ft. maximum
   • Can be created from an attached garage
   • Cannot be detached
   • JADUs cannot be expanded an additional 150 sq. ft. for ingress or egress, this is only for converted ADUs

3. One New Construction, Detached ADU (Gov. Code 66323 Unit)
   • Can be within the front setback
   • Cannot exceed 800 sq. ft. maximum
   • See the Government Code for applicable height limits between 16 and 20 feet

4. One ADU Compliant with the Town’s Zoning Code Standards (Gov. Code 66314 Unit)
   • This unit may be new construction or conversion and can be attached, detached, conversion, or conversion plus an addition
   • These units utilize the Town’s Zoning Code Standards for ADUs such as size of structure, height, setbacks, floor area, architectural design, etc.

On Multi-Family Zoned Lots

If your property has an existing or proposed multi-family development:

• Converted ADUs:
  • Up to 25% of existing units (minimum of 1)
• Detached ADUs:
  • Up to 2 (if new multi-family)
  • Up to 8 (if existing multi-family), not exceeding existing unit count
• Attached ADUs:
  • 1 new attached unit compliant with Gov. Code 66314 

Per State law and Windsor’s Zoning Code, ADUs & JADUs cannot be used as a short-term rental.

For a JADU built without its own private bathroom, the owner is required to live on-site, in the main dwelling or JADU. For the complete list of restrictions that must be included in the deed, here is a link to the section in the Town's Zoning Code.

ADU amnesty refers to the process of legalization and issuance of permits for an ADU or JADU originally built without permitting approval. State law requires that jurisdictions issue permits for certain existing ADUs and JADUs originally built prior to January 1, 2020, and eliminate financial penalties to property owners who opt to legalize their unpermitted ADU or JADU. The full text of AB 2533 may be viewed at the following  link, which has been adopted in California Government Code Section 66311.7. Contact Planning staff for assistance with determining eligibility, adu@townofwindsor.ca.gov.

The Building Division has an ADU Building Permit Submittal Checklist to ensure the ADU is processed as efficiently as possible. Click here to access the checklist.

Prior to finaling the permit, you must also submit the Address Application Form and ADU Acknowledgement Form with the submittal.