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What are the requirements to build ADU in Walnut?
Constructing an ADU in Walnut offers the chance to increase your living area and create customized spaces like a home office or recreation room. To ensure the success of your ADU project, it's important to grasp local regulations and assess the financial impact of building in Walnut. This guide offers in-depth information on Walnut's ADU regulations and important financial factors, aiding you in effectively planning and completing your project.
ADU regulations for properties with a single-family home
How many ADUs can you build in Walnut?
In Walnut, each single-family lot is allowed one ADU, which can be built either within the existing space or in a proposed area, regardless of whether it is attached or detached from the primary building.
How large can an attached ADU be in Walnut?
In Walnut, attached ADUs cannot be larger than 50 percent of the size of the main dwelling. Additionally, the maximum area for an ADU is 850 square feet, or 1,000 square feet if it has more than one bedroom. However, there's an allowance for constructing an ADU of at least 800 square feet.
How large can a detached ADU be in Walnut?
Detached ADUs should not go beyond 50 percent of the living area of the main dwelling or 1,200 square feet, whichever is smaller.
Can I build a 2-story ADU in Walnut?
No, ADUs in Walnut are limited to one story only.
Is there a minimum size for an ADU?
No, there is no minimum size requirement for ADUs in Walnut.
Can I convert the existing space to an ADU?
Yes, converting existing space into an ADU is allowed in Walnut, and you have the option to expand it by up to 150 square feet beyond the current dimensions of the accessory structure for ingress and egress.
What is the maximum height for an ADU?
The maximum height allowed for an ADU on a property with a single-family house is 17 feet.
ADU regulations for properties with a multi-family building
How many ADUs does Walnut allow for multifamily properties?
Multifamily properties can have a maximum of 25% of the current number of units as interior ADUs, with at least one unit allowed. Additionally, up to two detached ADUs can be constructed.
How large can an attached ADU for a multifamily building be in Walnut?
Attached ADUs in Walnut are restricted to no more than 50 percent of the primary residence's size. Additionally, the maximum area for an ADU is 850 square feet, or 1,000 square feet if it contains more than one bedroom. However, there's flexibility to construct an ADU of at least 800 square feet.
How large can a detached ADU for a multifamily building be in Walnut?
For a multifamily building in Walnut, detached ADUs are limited to a maximum of 50% of the living area of the main dwelling or 1,200 square feet, whichever is smaller.
Can I stack detached ADUs on top of each other?
No, stacking detached ADUs is not allowed. Instead, adding an ADU above an existing detached structure, such as a garage, is allowed.
Can I attach two ADUs to each other?
No, attaching two ADUs to each other is prohibited in Walnut.
Can I convert the existing space to an ADU?
Yes, you can convert existing space into an ADU in Walnut for multifamily buildings, and you're allowed to expand it by up to 150 square feet beyond the current dimensions of the accessory structure for ingress and egress.
What is the maximum height for an ADU on a property with a multi-family building
Similar to single-family properties, the maximum height allowed for an ADU on a property with a multifamily building in Walnut is 17 feet.
What ADU types are allowed to build in Walnut?
Walnut allows various types of ADUs, such as:
(A) Detached ADU: A completely independent structure separate from the main home.
(B) Attached ADU: A newly constructed addition directly connected to the primary dwelling.
(C) Converted ADU: The alteration of a non-livable space, like a garage, shed, or storage room, into a functional living area with a kitchen or kitchenette and a bathroom.
Converting existing buildings into ADUs provides more flexibility, as setbacks and height limits typically don't apply. These structures can also be expanded for additional room. However, renovating older buildings may reveal hidden problems that could increase costs.
ADU setbacks from the property lines and other buildings
What are the required setbacks for an ADU in Walnut?
In Walnut, ADUs are required to have a minimum setback of 4 feet from the side and rear yards. The city has not provided specific regulations for corner or through lots.
What is the minimum distance the ADU must have from the existing structures?
The minimum distance an ADU should be from existing structures in Walnut is 10 feet.
Are setbacks required when converting existing structures into ADU?
No. There's no need for setbacks when converting existing living spaces or accessory structures into ADUs in Walnut.
Can I build an ADU in the front yard of my house in Walnut?
Yes, but only if the property lacks sufficient space for an 800 sq ft ADU. Zoning setback requirements should still be followed.
Design requirements for ADU
How many bedrooms can an ADU have?
In Walnut, an ADU can have at least one bedroom unless it's proposed as a studio unit.
Does an ADU need to have a kitchen?
Yes, in Walnut, an ADU should have a full kitchen for cooking, unlike JADUs that only need efficiency kitchens.
Does an ADU require independent utility meters?
In Walnut, independent connections of utility meters between the ADU and the main unit are not allowed.
What is the minimum ceiling height?
The minimum ceiling height in Walnut is 7 feet, as required by the California Building Code.
Find out the maximum ADU size for your property here
The parking requirements for ADU
What is the parking requirement for an ADU in Walnut?
In Walnut, the parking requirement for an ADU is one off-street parking space per ADU or bedroom, with minimum dimensions of 10 feet in width and 20 feet in depth. Exceptions include if the ADU is within half a mile of a permanent transit stop, in an architecturally or historically significant district, entirely within an existing primary residence or accessory structure, or within 500 feet of a publicly designated car share location.
Where can I have a parking space on my property?
Parking spaces for ADUs in Walnut can be located within a setback area or as tandem parking in designated locations.
How to get permits for your ADU
How long does it take to get an ADU permit in Walnut?
The permit approval process usually takes around 3.5 to 4 months. Once the permit drawings are finalized, you or your architect should submit them for a Plan Check. It’s recommended to meet with a city planner ahead of time to review your application.
Once submitted and fees are paid, the city has up to 2 months to confirm whether the application is complete. If there is no response during this period, the permit will be automatically approved. If revisions are required, your designer will need to make the necessary adjustments and resubmit the application. The application should meet ADU regulations, and missing information alone will not lead to a denial. The estimated Plan Check fee for ADUs in Walnut is $4,029.
Does Walnut require in-person submission of plans for an ADU?
No, planning applications can be submitted digitally in Walnut, so in-person submissions are not required.
Does Walnut require coastal development permits?
No, there's no need for coastal development permits in Walnut.
When do you need a licensed professional to design an ADU in Walnut?
In Walnut, whether a licensed professional is needed to design an ADU is determined by how complex the project is.
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How much does it cost to build an ADU in Walnut?
Building an ADU in Walnut typically involves budgeting approximately $380 per square foot, which covers expenses such as permits, architectural design, and engineering services. For instance, constructing a 900-square-foot ADU would generally amount to around $390,000, including both soft and hard costs.
Is it profitable to build an ADU in Walnut?
Determining the financial feasibility of constructing an ADU in Walnut requires comparing construction costs with local real estate market values. For example, a 900-square-foot ADU could potentially be valued at about $540,000. Considering construction expenses of approximately $390,000, this indicates a potential return on investment of 37%.
Additionally, profitability can also be assessed by considering potential rental income or the benefits of accommodating family members on the same property.
Can you sell an ADU in Walnut?
California's AB 1033 permits local authorities to create guidelines for the sale of ADUs and primary residences as condominiums, as long as they follow the existing ADU development rules.
In Walnut, the sale of an ADU is subject to local regulations, which specify that it can be sold if constructed by an approved nonprofit organization, if a recorded tenancy in a common agreement is in place, or if the city permits the separate sale of both the ADU and the primary residence as distinct condominiums.
Are ADUs rent-controlled in Walnut?
No, in Walnut, ADUs are not covered by rent control laws. They are considered new constructions and are exempt from regulations like AB 1482, allowing landlords to adjust rents annually. This exemption applies to buildings that are at least 15 years old.
How do I get money to build an ADU in Walnut?
Homeowners in Walnut can apply for the CalHFA's ADU grant program, administered by the California Community Economic Development Association (CCEDA). This program offers eligible homeowners grants of $40,000 to cover pre-construction expenses for ADU construction. Moreover, more than half of these grants are reserved for low-income households, enhancing affordability.