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(925) 239-4165 ext: 160
Schedule ADU Consultation (925) 239-4165 ext: 160

Walnut Creek ADUs

Everything about building Accessory Dwelling Units in Walnut Creek, CA

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The city government of Walnut Creek has updated its local zoning codes to comply with the State ADU mandate.
The California Building Code (CBC) 2019 is adopted.

Last Updated 10/13/20



hintsights

City Hint: The city permitted a total of 13 ADU projects in the past year of 2019, which is below the average compared to other cities in California.


Number of ADUs allowed:

1. Lots with a single family dwelling:
Either one (1) attached accessory dwelling unit constructed at the same time as a new single family dwelling; one (1) attached accessory dwelling unit located within the footprint of an existing single family dwelling, plus up to 150 square feet of additional floor area if limited to accommodating ingress and egress; or one (1) detached accessory dwelling unit located within the footprint of an existing accessory structure, plus up to 150 square feet of additional floor area if limited to accommodating ingress and egress; and
ii. One (1) detached accessory dwelling unit;

2. Lots with an existing multiple family dwelling:
i. Multiple attached accessory dwelling units on a lot containing a multiple family dwelling, not to exceed twenty-five (25) percent of the number of existing dwelling units contained within multiple family dwellings; and
ii. Two (2) detached accessory dwelling units

Types of ADUs allowed:

Detached ADU, Attached ADU, Junior ADU are allowed. Accessory Dwelling Units may be new construction or converted from existing space. Junior Accessort Dwelling Unit (JADU)s must be converted from existing space.

Lot size:

ADU projects on single family or multi-family residential parcels will not be subject to the minimum lot size of the underlying local zoning code or by special ordinance. ~ AB68 & AB881 Update

ADU size:

ADU floor area is based on the Size of the lot:
14,999 square feet or less: 850 square feet for one bedroom, 1,000 square feet for a two bedroom
15,000 to 19,999 square feet: 900 square feet for one bedroom, 1,000 square feet for a two bedroom
20,000 square feet or more: 950 square feet for one bedroom, 1,000 square feet for a two bedroom

Attached accessory dwelling units shall not exceed fifty percent (50%) of the gross floor area of the main building, or a gross floor area of 800 square feet, whichever is more, when the main building is already in existence

The maximum gross floor area for a junior accessory dwelling unit shall be 500 square feet.

Setbacks:

No greater than a four (4) foot side or rear setback shall be required for an accessory dwelling unit constructed beyond the footprint of an existing building, unless the portion constructed beyond the footprint of an existing building does not exceed 150 square feet and is limited to accommodating ingress and egress

The minimum setbacks and courts shall be waived for an accessory dwelling unit constructed entirely within the footprint of an existing building, and for up to 150 square feet outside of the footprint of an existing building if the additional area is limited to accommodating ingress and egress; however, the accessory dwelling unit must still comply with all applicable provisions of Title 9.

Parking:

No parking spaces are required

Fire Safety:

Per state requirements.

Shape, materials and style:

ADUs must be designed to be architecturally consistent with the primary dwelling, including form, exterior siding and/or trim, roof materials and window placement and type. Any new entrances to an attached ADU must be located on the side or rear of the building.

Height:

The maximum building height shall be waived in the amount necessary to accommodate an accessory dwelling unit with a building height of up to sixteen (16) feet.

Design review:

The accessory dwelling unit shall be designed to be architecturally consistent with the main building, including building form, exterior siding and/or trim, roof form and materials, and window placement/type. Any new entrances to an attached accessory dwelling unit shall be located on the side or in the rear of the building.

Number of Bedrooms:

Not specified by State Standards.

Ownership:

Between between 2020 and 2025, owner occupancy requirements will not apply to new Accessory Dwelling Units. (applicable to new construction and conversion units) ~ According To SB13

Utility connections:

New construction or additions; Local utilities may only impose a connection fee or capacity charge if it is proportionate to the burden of the proposed ADU upon the water or sewer system, based on either its size or the number of its plumbing fixtures. This fee or charge cannot exceed the reasonable cost of providing service. Contact the utility districts listed below for more information.

Conversions; Local utilities are prohibited from requiring a separate utility connection for the ADU or imposing a related connection fee or capacity charge. Contact the utility districts listed below for more information.

Short term rentals

Short term rentals of 30 days or less require approval of a Conditional Use Permit (CUP).

Allowed Zones:

*** Beginning in 2020, according to state law, all residential zoning districts, including single-family and multi-family, are allowed to build Accessory Dwelling Units. ***

ADUs are allowed in all residential districts with a single family home on the lot with no more than one ADU permitted per lot.

Residential Building Code:

The California Building Code (CBC) 2019 is adopted.

Walnut Creek City Planning Offices
Permitting

Walnut Creek Planning & Zoning

1666 North Main Street Walnut Creek, CA 94596 Walnut Creek, CA 94596

Read Walnut Creek Housing Market Update

Call/Text ADU Operator (925) 239-4165
Dial Ext: 160
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ADU Design Library

Browse hundreds of models to find the right fit for your property.

ADU Model 850 sqft

W 25 ft L 17 ft

ADU Model 480 sqft

W 30 ft L 16 ft

ADU Model 300 sqft

W 25 ft L 12 ft


Customer Reviews


"Housable has been a great resource regarding my ADU project. I purchased both the Property and Design Reports. In both cases, they delivered as promised and on time."

Ed in Corona, CA

"My experience with Housable was exceptional. The team was extremely helpful and responsive. I am very satisfied and happy to have used these services. As a home owner I do not know the construction lingo or process but the Housable team very kind and helpful and patient with me. My expectations were exceeded. Thank you for everything."

Monica H. in Oakland, CA

"The property report was great! Made me feel like my project is feasible."

Alexandria in Santa Ana, CA



Complete 5-Step Process

Design
Browse hundreds of permit-ready ADU designs and order one to customize to your needs.
Marketplace
Connect with local contractors to get site visits and cost estimates for your project.
Customization
Mark up changes to your plans and provide critical info needed to permit your project.
Permits
Finalize your project blueprints to submit for building permits.
Construction
Select your contractor and build your project.


What our customers say:



Customer Reviews


"My permits were APPROVED, thank you for all your hard work. I am in the process of meeting with contractors. "

Mary S. in San Jose, CA

"I just wanted to let you know that the permit process has been completed and we are currently in the construction phase. The work you guys did was great and I will definitely be using this service again in the future. I will keep you guys updated on anything important. Thanks!"

Patrick L. in Orange County, CA

Detached ADU - Completed in 2020
1,003 sq. ft., 3 bed, 2 bath

Estimate Your ADU Potential
Financing
Costs / ROI

SELECT ADU SIZE & TYPE

APPRECIATION ESTIMATE

* upon completion of ADU

CONSTRUCTION COST ESTIMATE

* based on local average price per sqft

RENTAL ESTIMATE

* estimated by location

MORTGAGE ESTIMATE

* 30 years / 5% interest rate / 20% down payment

SELECT ADU SIZE & TYPE

Size: 500 sqft

BASED ON LOCAL AVERAGE PROPERTY DATA & VALUE

Appreciation Estimate = (Base Value: $) / (Home's Living Space: sqft) * (ADU's Living Space: sqft)

Rental Estimate = (Rent Per Sqft: $4.42) * (ADU's Living Space: sqft)

Check your property's zoning, browse designs & get contractor estimates for your ADU project:

Everything you need to get accurate estimates from contractors for your ADU project. Get help with ADU feasibility, design, permitting and sourcing contractors for your project in one place.

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