Accessory dwelling unit builders near me

Looking for accessory dwelling unit builders near me in Ontario, CA? Call AccessoryDwellingUnit Solutions for a contact a provider — no obligation. Licensed adu builders serve Ontario and the surrounding area, and you'll get straight answers on timing and what affects the price.

Last updated: September 24, 2026

What affects the price

Building an ADU involves several moving parts that shape your total budget. The biggest factor is whether you choose a prefabricated unit or a custom build on-site. Site preparation is also significant; if your land requires extensive grading, utility trenching, or foundation work, costs will climb. Your choice of finishes—like kitchen cabinetry, flooring, and siding materials—also shifts the bottom line. We help you navigate these variables to find a setup that fits your property. Exact pricing confirmed free on the call.

About this service

Local builders provide the labor and project management needed to turn an empty backyard space into a functional living area. You need them when you have a vision for a guest house or rental but need a team familiar with your specific regional climate and local building department inspectors. Hiring nearby crews often simplifies logistics and ensures that your builder has established relationships with local supply houses and inspectors.

Frequently asked in Ontario

What are the disadvantages of ADUs?

Potential disadvantages include the significant upfront cost of construction and the time needed for permit approvals. There can also be specific zoning ordinances or homeowner association rules to navigate. Careful planning for utilities and site access is crucial. The pros you speak with can help you anticipate these.

How much does an ADU cost in California?

The cost of an ADU in California varies widely based on size, design complexity, and the quality of finishes chosen. Site preparation, including any necessary utility upgrades or foundation work, also significantly impacts the total price. For an accurate estimate specific to your Ontario location, a consultation with a local builder is recommended.

What are the rules for ADUs in California?

Is ADU allowed in Maryland?

This question pertains to Maryland, not Ontario, California. For information regarding ADUs in Maryland, you will need to consult their specific local regulations. However, if your interest is in the Ontario area, we can assist you in finding qualified local professionals.

What are the rules for ADU in California?

California has specific statewide ADU laws, and Ontario, being in California, adheres to these. Local municipalities also have their own additional rules to follow. The pros you'll speak with understand all of Ontario's specific ADU requirements.

Also serving nearby: Chino · Rancho Cucamonga · Jurupa Valley · Pomona · Fontana

All cities in California →

More on this: HUD ADU resources — ADU policy and financing research.

Service area details

182,457residents

3,650per sq mile

4ZIP codes served

Serving all of Ontario — population 182,457; about 3,650 residents per square mile across 50.0 sq mi. ZIP codes covered include 91758, 91761, 91762, 91764.

Neighborhoods served in Ontario: Etiwanda, Vineyard, Central Ontario, West Ontario, South Ontario, Chino — and every surrounding area.