Accessory dwelling unit near me — St. Louis, MO

Last updated: September 24, 2026

What affects the price

Building an ADU is a custom project, so costs vary based on your specific choices. Site conditions are the biggest factor; if your land requires significant grading, utility extensions, or foundation work, those expenses add up quickly. Choosing high-end finishes, custom cabinetry, or complex roof lines will also push the budget higher compared to a standard design. Prefabricated units often offer predictable costs, while custom site-built structures allow for more flexibility but can be harder to estimate upfront. Exact pricing confirmed free on the call.

About this service

Searching for an ADU near you helps you find design and construction firms that are already familiar with your local zoning laws and permit offices. This is a great starting point when you want to see what is possible on your specific piece of land. Local experts can visit your site to determine if your lot qualifies for a detached unit or garage conversion based on local setbacks and utility access. Exact pricing confirmed free on the call.

Frequently asked in St. Louis

Also serving nearby: O Fallon · Springfield · Columbia · Champaign · Peoria

All cities in Missouri →

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

Service area details

Serving all of St. Louis — population 281,754; about 4,565 residents per square mile across 61.7 sq mi.

Neighborhoods served in St. Louis: The Hill, Tower Grove South, Central West End, CWE, Benton Park, Soulard — and every surrounding area.