Everything about building Accessory Dwelling Units in Ventura, CA
Check your property's zoning, browse designs & get contractor estimates for your ADU project:
Last Updated 09/19/21
Number of ADUs allowed:
Single-Family Properties - All single-family homes can have one ADU. Additionally, properties with single-family homes that are owner-occupied can have one ADU and one JADU with a recorded statement that the property owner will occupy one of the units.
Multi-Family Properties – There are a few ADU options for multi-family properties. You can pick one of the following three options:
An ADU can be added for up 25% of the existing units. The ADU(s) have to be within livable space inside the existing building(s) the units are in.
One ADU can be added in an existing structure on the property that is currently non-livable, such as a garage.
Up to two ADUs can be built in a new structure(s) on the property. These structure(s) would be detached from the existing building(s) and are limited to 16 feet in height with at least a four-foot rear and side yard setback.
Types of ADUs allowed:
Detached ADU, Attached ADU, Junior ADU are permitted. ADUs may be new construction or converted from existing space. JADUs must be converted from existing space.
Single family and multi-family residential properties will not be subject to the minimum lot size of the underlying zoning district or by ordinance for ADU projects. ~ AB68 & AB881 Update
A studio or one-bedroom ADU can be up to 850 square feet.
An ADU with more than one bedroom can be up to 1,000 square feet, except if it is attached to an existing single-family home, then it is limited to 50% of the size of the house.
There is no size limit for converting an existing accessory structure, like a garage or shed, into an ADU.
A JADU can be up to 500 square feet and needs to be within the existing single-family home.
If you are building a new ADU that will be detached from the main residence or building(s), the ADU needs to be at least 4 feet from the side and rear property lines and maintain the front yard setback required in the zone of the property.
A minimum 10-foot separation is needed between the new ADU and the main residence or other structures.
Setbacks do not apply when converting an existing accessory structure, like a garage, pool house, or detached recreation room into an ADU. Enlarging or modifying an existing structure for an ADU would require meeting the setbacks.
An ADU that is attached to the main residence must follow the same setbacks as the main residence.
(1.) Attached ADUs: An ADU that is attached to the primary residence shall comply with the height requirements applicable to the primary residence. (2.) Detached ADUs: An ADU that is detached from the primary residence shall not exceed a height of 14 feet and one story, except as follows: a detached ADU may be up to 22 feet on a second floor if either (i) it is not located within the rear setback area or (ii) it is constructed above and within the existing footprint of an existing garage and/or existing building.
Accessory dwelling units shall not be required to provide fire sprinklers if they are not required for the primary residence and may employ alternative methods for fire protection. (State requirements)
Shape, materials and style:
Generally, the design of the ADU should be compatible using similar colors and materials to the main residence or building(s) on the property.
Design and Features:
1. The ADU's color and materials shall match the primary residence.
2. The ADU shall not have any second-story outdoor balcony, deck, or patio closer than ten feet from any property line.
3. If an automatic sprinkler system is required for the primary residence, the ADU must also provide an automatic sprinkler system.
4. The main entrance to the dwelling unit shall be accessed from the side yard setback, side street setback, or rear yard setback.
5. For any second-story ADU, including any ADU proposed above a garage, all exterior windows that face rear or side yard areas of an adjacent property, are not separated by an alley, and are closer than ten feet from the property line shall be fitted with translucent glazing and be either fixed (i.e., inoperable) or of an awning style with a maximum opening angle of 25 degrees.
Maximum heights only apply when building a new ADU or expanding an existing structure for an ADU:
- 16 feet for a one-story ADU
- Up to 22 feet on a second floor if it is not in the rear setback area, or constructed above an existing structure within the existing footprint
State Standards don't require any additional design review.
Number of Bedrooms:
Not specified by State Standards.
Between between 2020 and 2025, owner occupancy requirements will not apply to new ADUs. (applicable to new construction and conversion units) ~ SB13 Update
Fees and utility connections.
A. The property owner shall pay all sewer, water, school district, and other applicable fees, including development impact fees.
B. The property owner shall pay all applicable connection fees and capacity charges, including sewer connection fees pursuant to Section 22.210.030, except as provided in subsections C. and D. below.
C. An ADU specifically exempted under Government Code Section 65852.2(e) and (f), which is created by the conversion of an existing space pursuant to Section 24.430.040.H., shall not pay any related connection fee or capacity charge.
D. An ADU shall be equipped with a water sub-meter, pursuant to Section 22.130.015, but shall not require a separate water or sewer utility connection from the Primary Dwelling Unit.
E. If an ADU will use a private sewage disposal system, the property owner shall obtain approval by the Los Angeles Regional Water Quality Control Board and the City Building and Safety Division.
ADUs are not permitted on any real property listed in the California Register of Historic Places, or designated as a historic landmark or located in a historic district overlay zone under Chapter 24.455, except following design review pursuant to Section 24.455.620 and Chapter 24.340.
ADUs are not permitted in the Coastal Zone, except within the Downtown Specific Plan and a portion of the Midtown Corridors Area.
*** Beginning in 2020, according to state law, all residential zoning districts, including single-family and multi-family, are allowed to build Accessory Dwelling Units. ***
Zoning Districts: R-1 (Single-Family Zone), R-2 (Two-Family Zone), or R-3 (Multiple-Family Zone), as shown on the Zoning District Map.
Lot Coverage: The combined total of both the primary residence and ADU shall not exceed the maximum lot coverage applicable to the lot, plus five percent. The combined rear yard lot coverage shall not exceed the maximum applicable to the lot, plus ten percent.
Conversion of Existing Space: Conversion of existing space within a single-family residence or within a legally permitted accessory structure to an accessory dwelling unit shall be permitted by right, provided that the proposed accessory dwelling unit has independent exterior access from the existing residence, and the side and rear setbacks are sufficient for fire safety and as required per the adopted California Building Standards and local ordinance.
Building and safety requirements.
An ADU will be subject to Building and Safety requirements of the City, including, but not limited to, the following:
A. Structural Assessment: An ADU conversion of existing structures built prior to 1970 will require structural assessment in accordance with ASCE 41-13.
B. Utility Equipment: Each ADU must have its own water heater and space heating.
C. Building and Safety Permits: Each ADU must obtain all required Building and Safety permits in compliance with current California Building Standards Codes (California Code of Regulations, Title 24) and local ordinances.
Residential Building Code:
The California Building Code (CBC) 2019 is adopted.
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