Accessory Dwelling Units (ADUs) are gaining traction in Riverside. These secondary units, sometimes called granny flats or casitas, offer extra living space, rental income, or a spot for family. But before you start building, you’ll need to navigate Riverside’s ADU laws, requirements, and the permit process. This guide breaks it down step by step, keeping things practical and straightforward.
Types of ADUs in Riverside
Riverside allows several ADU types:
- Detached ADUs: Standalone structures, often in the backyard.
- Attached ADUs: Built as an extension of the main home or converted from spaces like garages.
- Junior ADUs (JADUs): No larger than 500 square feet, contained within the existing home, often using an existing bedroom. JADUs need a separate entrance but can share a bathroom with the main house.
Each type serves different needs. Detached units offer privacy. Attached and junior units make use of the existing space. The city’s rules apply differently to each, so pick the option that fits your property and goals.
Zoning and Land Use
Riverside’s zoning code is the first hurdle. All residential properties are eligible for at least one ADU, but there are details to watch for:
- Setbacks: ADUs must be at least four feet from the side and rear property lines.
- Lot Coverage : Detached ADUs can be up to 1,200 square feet. Attached ADUs can cover up to 50% of the main house’s floor area.
- Height: Generally, ADUs can be up to 16 feet tall, but this can vary by neighborhood.
- Parking: Detached ADUs usually require one parking spot, unless your property is within half a mile of public transit. Interior ADUs inside the existing house are often exempt from extra parking.
Building Code Requirements
Every ADU must meet California Building Code standards. This covers:
- Foundations, walls, and roofs: Must be structurally sound.
- Utilities: Detached ADUs usually need separate utility connections. Interior or junior ADUs can share utilities with the main house.
- Safety: Smoke detectors, carbon monoxide alarms, and proper exits are required.
Permit-Ready ADU Plans
Riverside offers free, pre-approved ADU plans. These plans save time and money by reducing design errors and speeding up the approval process[3][4]. You can choose from several architectural styles—Traditional, Craftsman, and Spanish. Using these plans means fewer surprises during the city review.
Steps to use permit-ready plans:
1. Select a plan: Download the PDF from the city’s website.
2. Complete a site plan: Use a map tool to mark where the ADU will go on your property.
3. Fill out the cover sheet: Add your property’s details.
4. Complete required forms: This includes a Hold Harmless Agreement and a Permit Ready Clearance Form.
The Permit Application Process
Here’s the process, boiled down:
1. Prepare your documents :
- Detailed ADU plans (pre-approved or custom).
- Site plan showing property lines, existing structures, and the new unit.
- Energy compliance documents (Title 24).
- Structural calculations, if needed.
- Completed application forms.
2. Submit online: Riverside uses the PLUS Online portal. Create an account and upload your documents. The portal has instructional videos if you get stuck.
3. City review: Officials check your plans for code compliance. Expect a review period usually around 60 days. If corrections are needed, you’ll get a list to address.
4. Inspections: After approval and during construction, the city will inspect at key stages, foundation, framing, electrical, plumbing, and final sign-off.
Permit Fees and Impact Fees
Permit fees for ADUs in Riverside range from about $3,000 to $9,000, depending on the size and complexity of the unit. For ADUs under 750 square feet, development impact fees are waived. Larger units pay fees based on their square footage and scope.
Fast Approval Tips
- Use pre-approved plans: Cuts down on review time and reduces back-and-forth with the city.
- Double-check your documents: Incomplete applications are the top reason for delays.
- Know your setbacks and lot coverage: Avoids red flags during review.
- If near transit, note it: You may be exempt from parking requirements, which simplifies approval.
- Respond quickly to corrections: The faster you fix issues, the sooner your permit moves forward.
Design Standards and Construction
ADUs must meet design guidelines for aesthetics and function. Riverside wants these units to blend into neighborhoods:
- Exterior materials : Should match or complement the main house.
- Roof pitch and style : Consistent with the existing home.
- Entryways : Separate entrance for JADUs; detached units need their own access.
Accessibility and energy efficiency are also required. Title 24 energy compliance is mandatory. If you’re converting a garage or other space, you may need to upgrade insulation, windows, and doors.
Ownership and Use
Riverside does not require owner-occupancy for ADUs. You can rent out both the main house and the ADU, or live in one and rent the other. There are no special deed restrictions just for building an ADU, but you must follow any existing property covenants or HOA rules.
Rental terms must comply with state law—no short-term rentals under 30 days unless local ordinances allow.
Utility Connections
- Detached ADUs : Usually need separate water, sewer, and electric meters.
- Interior/JADUs : Can share utilities with the main house.
- Fees : Connection and impact fees are set by state law and local ordinance. Check with your utility provider for current rates.
Common Questions
- How long does it take to get a permit?
Average is 60 days, but using pre-approved plans can speed things up.
- Can I build more than one ADU?
On a single-family lot, you can build one ADU and one JADU, as long as you meet all requirements.
- Do I need an architect?
Not if you use the city’s pre-approved plans. For custom designs, an architect or designer may be required.
- What if my property is in an HOA?
You must follow HOA rules in addition to city and state laws.
Final Thoughts
Building an ADU in Riverside is a practical way to add value, create rental income, or house a family. The city’s rules are designed to make the process manageable, especially if you use permit-ready plans. Stick to the steps, keep your paperwork tight, and don’t be afraid to ask city staff for help.
If you’re a professional looking for a side project or just want to maximize your property’s potential without a headache, Riverside’s ADU program is worth a look. And hey, if you ever wanted to be a landlord without buying a whole new property, this is your chance.
