The Basics of ADU Remodeling in the Inland Empire

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.

What Is an ADU?

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

Why Remodel an ADU in the Inland Empire?

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 for ADU Remodeling in the Inland Empire

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.

Converting Existing Structures Into ADUs

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.

ADU Design and Safety Requirements

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.

ADU Zoning Rules Vary by City

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

Top ADU Renovation Tips

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

Conclusion

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.