Premier ADU Builders in Corona, CA
At ADUs by Avatar , we help homeowners in Corona navigate the full ADU process — from feasibility and design to permitting and construction. Building an ADU in Corona is one of the smartest ways to add value, create rental income, and expand livable space without moving. Whether you’re planning a detached backyard ADU, a garage conversion, or a junior ADU (JADU), understanding Corona’s local permitting and zoning requirements is the first step toward a successful project.
Why Corona Homeowners Are Building ADUs
Corona continues to grow as one of the most desirable cities in Riverside County, especially for homeowners who want more space, flexibility, and long-term property value.
Many homeowners build ADUs in Corona to:
- Create long-term rental income
- Add a private space for aging parents or adult children
- Build a guest suite or home office
- Increase resale value with legal square footage
- Convert unused garages into livable space
ADU Types Allowed in Corona
Depending on your lot size, zoning, and existing home layout, the City of Corona may allow one or more of the following ADU options:
Detached ADUs
A standalone backyard unit that offers the most flexibility in design and long-term use.
Attached ADUs
An ADU connected to the primary home, often built as an addition.
Garage Conversion ADUs
Garage conversions are one of the most popular ADU options in Corona because they can be faster and more cost-effective than building from the ground up.
Junior ADUs (JADUs)
A smaller ADU (typically up to 500 sq ft) created within the existing home footprint.
Corona ADU Permits and Requirements
All ADUs in Corona require permits and must meet California Building Code and Title 24 energy standards.
Most ADU projects require:
- Building permits
- Electrical permits
- Plumbing permits
- Mechanical/HVAC permits
- Title 24 compliance
- Structural engineering (depending on the project)
We Handle the Full Permitting Process
Permitting can be one of the most stressful parts of building an ADU — especially for homeowners who don’t want to deal with plan check corrections, re-submittals, and city communication.
ADUs by Avatar manages the full permitting process, including:
- Confirming zoning and development standards
- Preparing plans for submittal
- Coordinating engineering and Title 24
- Submitting to the city on your behalf
- Responding to plan check corrections
- Coordinating inspections through construction
* In some cases, additional approvals may be required depending on your property location, existing utilities, or site conditions.
Corona vs. Unincorporated Riverside County
While many homeowners say they live in “Corona,” some nearby neighborhoods and rural pockets are actually unincorporated areas of Riverside County. That matters because ADU rules and permitting can be different depending on whether your property falls under:
- City of Corona jurisdiction, or
- Riverside County (unincorporated) jurisdiction
The ADU process, plan review, and development standards can vary depending on which agency has authority over your address.
If you’re not sure which jurisdiction your property falls under, we can confirm it during your ADU Assessment and guide you through the correct permitting process.
Explore Riverside County ADU Rules
If your property is located in an unincorporated area near Corona, your ADU may fall under county regulations instead of city requirements you can
Explore our Inland Empire ADU hub here
ADU Costs in Corona, CA: What Impacts Pricing
ADU costs in Corona vary depending on the type of unit and the conditions on your property.
Key factors that impact Corona ADU pricing include:
Garage Conversion Costs
Garage conversions are often more affordable, but costs can increase depending on:
- Electrical panel upgrades
- Plumbing trenching
- Insulation and HVAC requirements
- Structural upgrades and code compliance
Detached ADU Costs
Detached ADUs typically require a larger budget because they involve:
- New foundation and framing
- Full utility trenching
- Roofing and exterior finishes
- Full HVAC installation
- Site restoration after construction
Common Cost Surprises
Homeowners are often surprised by:
- Utility trenching distance
- Sewer connection location
- Electrical service upgrades
- Grading, drainage, or retaining wall needs
At ADUs by Avatar, we provide realistic cost guidance early so you can plan confidently before moving into full design.
ADU Timeline in Corona: Step-by-Step
Every project is different, but most Corona ADU builds follow a similar timeline:
Step 1: ADU Assessment and Feasibility Study (2-4 weeks)
Step 2: Design + Floor Plans (2–6 weeks)
Step 3: Engineering + Title 24 (2–6+ weeks)
Step 4: Permit Submittal + City Review (6–14+ weeks)
Step 5: Construction + Inspections
-
Garage conversion ADU: 8–16 weeks
-
Detached ADU: 16–28+ weeks
Step 6: Final Approval + Move-In
*Timelines vary based on project scope, property conditions, city plan check workload, and the number of revisions required during permitting. The ranges above are general estimates and are not a guarantee of approval or completion dates.
Serving Riverside County Homeowners
Looking for ADU construction outside Corona ? We also serve homeowners throughout San Bernardino County!