The Inland Empire continues to grow quickly — and as home values rise across Riverside County and San Bernardino County, more homeowners are exploring ADUs as a way to add living space, increase property value, and create housing options for family or renters.
If you already have an ADU, garage, or detached structure on your lot, remodeling may be the most cost-effective way to transform it into a modern, functional unit.
In this guide, we’ll cover the essentials of ADU remodeling in the Inland Empire so you can start your project with a clear understanding of what to expect.
An ADU (Accessory Dwelling Unit) is a secondary residential unit located on the same lot as an existing home. ADUs can be built as detached backyard units, attached additions, or converted spaces like garages.
Many Inland Empire homeowners use ADUs for:
Rental income
Housing for adult children
Aging-in-place family needs
Guest space
Multi-generational living
In the Inland Empire, ADU remodeling is especially popular because many properties have:
Larger lots
Detached garages
Existing structures that can be converted
Space for additional utility runs
Homeowners remodel ADUs to:
Improve comfort and functionality
Upgrade old utilities
Add legal livable square footage
Increase long-term property value
Create a unit that can generate income
Permits are required for most ADU remodels, especially when the project includes structural work or utility changes.
Permits commonly include:
Building permits
Electrical permits
Plumbing permits
Mechanical/HVAC permits
Zoning or planning approvals (depending on city)
Each city — like Corona, Riverside, Ontario, Fontana, or San Bernardino — may have different requirements.
One of the biggest advantages in the Inland Empire is the ability to convert existing structures, especially garages and detached buildings.
Conversions typically require upgrades such as:
Insulation and drywall
New windows and doors
Plumbing and sewer connections
Electrical panel upgrades
Fire-rated construction
Even if the structure is already there, it still needs to meet current building standards to pass inspection.
ADUs must meet modern building and safety codes. Remodel requirements often include:
Proper exits and egress windows
Smoke and carbon monoxide detectors
Heating and ventilation
Updated electrical and plumbing systems
Minimum room and ceiling standards
If the ADU is meant for an older family member, accessibility upgrades like walk-in showers and minimal step-ups are strongly recommended.
The Inland Empire includes many fast-growing cities, and ADU rules vary depending on where you build.
Zoning may affect:
Maximum ADU size
Setbacks
Height limits
Parking rules
Utility requirements
Fire department access requirements
For the smoothest remodel:
Confirm code requirements early (before design begins)
Budget for utility upgrades if your unit is older
Design for efficiency (small units need smart layouts)
Work with an ADU contractor familiar with Inland Empire permitting
ADU remodeling in the Inland Empire is one of the best ways to expand your property’s potential without buying a new home. With the right planning, permitting, and professional support, you can turn an outdated space into a high-quality unit that serves your family — and adds long-term value.