ADU Construction Cost: Price and Benefits of Having an ADU

SERVING AUSTIN, SAN ANTONIO, HOUSTON
And Surrounding Areas

Small House Solutions Offers the Following Services at NO COST to You

Zoom Consultation
No-cost ZOOM consultation for in-depth discussions.

Two people sitting at a conference table

Phone Consultation
Personalized solutions for your inquiries directly.

a woman holding a phone and looking at a computer screen

If you are planning an accessory dwelling unit (ADU) in Austin, San Antonio, or Houston, the first question is cost. This guide stays away from price ranges and focuses on what changes the size of the project, plus the benefits homeowners want.

You will leave with questions, a checklist, and next steps today.

Table of Contents

What an ADU is in plain terms

The big drivers that shape ADU construction cost

Local rules still matter in each metro

Benefits of adding an ADU

A practical checklist before you start design

A simple ADU project flow

Looking for a ADU Builder?

Frequently Asked Questions

What an ADU is in plain terms

An ADU is a smaller, independent living space on the same lot as a primary home, and it can be attached to the main house or built as a separate structure, as described by Local Housing Solutions.

The big drivers that shape ADU construction cost

Final Living Kitchen

Most budgets move because the scope changes, not because one line item is a little higher or lower. A guide from Money explains that scope can shift based on size, design, location, permitting, and utility connections.

Site conditions and prep work

Start with the ground and the path to the build area. Ask:

Is the build area flat, or does it need grading and drainage work?
Are there large trees, easements, or tight access points to work around?
Where will materials be staged, and how will crews reach the site?

Utilities and connections

Utility scope is a common place for surprises. Ask early:

Where will water, sewer, and electric lines tie in?
Will any existing service need an upgrade to support the new unit?
Will the ADU share systems with the main home, or have separate runs?

Design choices that change complexity

Focus on decisions that add complexity:

How many rooms do you need, and how much storage?
Do you want a full kitchen, a compact kitchenette, or something in between?
Do you need extra sound control, privacy, or accessibility features?

Permits, reviews, and required documents

Permitting affects effort, schedule, and coordination. The City of Austin lists steps such as verifying the property can support an additional dwelling unit, requesting an address, submitting required documents, and moving through plan review.

Timeline and scope changes

A steady plan helps protect your budget. Keep decisions organized, confirm selections early, and minimize midstream changes once construction begins.

Local rules still matter in each metro

Local zoning and development standards can change what is allowed and what must be reviewed. Use your city’s planning resources to confirm the basics before you commit to a layout.

Deed restrictions and HOA rules can affect the plan

The City of Houston Planning and Development Department advises property owners to verify whether deed restrictions allow ADU construction and rental in their neighborhood.

Benefits of adding an ADU

Here are common goals homeowners share when they add a second living space.

More space for family, with privacy

An ADU can give a parent, adult child, or returning family member a place that feels independent while staying close.

Aging in place and caregiver support

AARP explains that ADUs can support aging in place by offering a smaller home on the same property, and they can also serve as living space for a caregiver or a relative who needs care.

Flexible use over time

An ADU can shift from guest space to a family suite, then to a long-term rental, then back to a home office, depending on what your household needs.

A practical checklist before you start design

Use this list to reduce rework:

Confirm zoning and setback rules for your address.
Identify utility tie-in points and access routes.
Check for deed restrictions and HOA requirements.
Decide which ADU type fits your lot: detached, attached, or a conversion.
Write down your must-haves and nice-to-haves so the scope is clear.

A simple ADU project flow

Use this flow to plan your project:

Feasibility and site review
Design and construction drawings
Permits and plan review
Construction and inspections
Final sign-off and move-in

Looking for a ADU Builder?

If you want a clear plan and a team that can guide you from concept to completion, we can help you map your scope and next steps. Book our ADU Builders to talk through your property and goals.

Frequently Asked Questions

What affects ADU construction cost the most?

Cost changes when the scope changes. Start by defining your ADU type, the level of finish you want, and how utilities will connect so fewer decisions are left to the field.

Is a detached ADU harder than a garage conversion?

It depends on your lot and your existing structure. A conversion may reduce exterior work, while a detached unit can offer more privacy and placement options.

How can I avoid budget surprises without using a price range?

Use a checklist and confirm constraints early. The more you lock down site access, utilities, and the permit path before design is final, the fewer late changes show up later.

Do I need to check deed restrictions even if the city allows an ADU?

Yes. Private rules can apply alongside city rules, so review deed restrictions and HOA documents before you commit to a plan.

What should I do first if I am just starting?

Write down your main goal for the ADU, then confirm whether your property can support it. Once you know the basics, you can choose the right ADU type and move into design.

Custom Design Packages Tailored to Your Project

Experience a design process that’s truly personalized. At Small House Solutions, our custom design packages are crafted to fit your specific project requirements. We offer a wide range of 3D modeling and rendering services, allowing you to visualize your new space from every angle before construction even begins.

Our comprehensive, full-service approach ensures a seamless journey—from your initial vision, through the design and build phases, to the final development. We manage every aspect of your project under one roof, providing you with peace of mind and a single point of contact. Ready to bring your dream space to life?

Let’s start designing, Today!

Custom home Design Packages Tailored to Your Project

WHAT OUR CUSTOMERS THINK ABOUT US

Real feedback from our valued customers

Peter Ruehlen

August 2023

Amazing company all around. Hands down some of the best contractors I have ever worked with. High quality top tier construction, incredible management and subs.

Brendan Turrell

February 2024

The project was done ahead of schedule and exceeds our expectations. I have already recommended this company to friends and will use them again whenever I have a construction project.