Austin's ADU rules changed under the HOME amendments, and the city's own page buries the numbers behind half a dozen sub-pages. We handle the permit work end-to-end — from zoning verification to Certificate of Occupancy — so you spend your time on design choices, not on hold with Development Services.
The City of Austin's ADU documentation is technically accurate and almost completely unreadable. The actual rules live across the Land Development Code, two HOME ordinance PDFs, a half-dozen interpretive memos, and an AB+C Portal that homeowners typically see for the first time when they're already mid-application. Most people building their first ADU spend the first month just figuring out which rules apply to their lot.
That uncertainty is the part of the project we've done a hundred times. Every plan we sell has been through Austin Residential Plan Review, which means the dimensional checks, the impervious-cover math, and the IRC fire-separation details are already calibrated against what Travis County reviewers actually flag. You aren't discovering Austin's ADU rules with us — you're inheriting the version of them we've been refining since the HOME amendments first passed.
Service area
Serving Austin and the surrounding metro: Downtown Austin, South Austin, East Austin, North Austin, West Austin, Bouldin Creek, Hyde Park, Tarrytown, Clarksville, Mueller, Crestview, Allandale, Travis Heights, Zilker, Barton Hills, Cherrywood, Round Rock, Pflugerville, Cedar Park, Leander, Georgetown, Hutto, Bee Cave, Lakeway, West Lake Hills, Rollingwood, Sunset Valley, Manor, Buda, Kyle, and Dripping Springs. Travis, Williamson, and Hays counties.
Bryker Woods Garage Apartment · Austin, TX — built under current Austin ADU rules.
The actual steps a homeowner faces
Austin's ADU process is a seven-step flow, but the names the city uses don't map cleanly to what you'll actually be doing day-to-day. Here's what the decision points look like in practice.
1. Confirm eligibility
Under the HOME Phase 1 amendments, up to three dwelling units are allowed on lots zoned SF-1, SF-2, or SF-3 that are at least 5,750 square feet. Smaller lots between 1,800 and 5,749 square feet are eligible for a single Small Lot Single-Family unit under HOME Phase 2. Eligibility also depends on deed restrictions, which the city doesn't check for you — a 1960s-era restrictive covenant can still block an ADU even when the zoning allows it. We pull both records before quoting the project.
2. Get an address
Each new unit needs its own address from Address Management Services before the building permit application goes in. This is a small form, but skipping it strands the permit in intake. We file it the same week we kick off design.
3. Site plan and zoning math
Two-unit and three-unit projects in Austin are capped at 40% building coverage and 45% impervious cover. Carports and garages count toward both. Side setbacks come from the base zoning district's row of the LDC § 25-2-492 table, not from a separate ADU rule. The Subchapter F 32-foot height cap doesn't apply to multi-unit projects — it only governs single-family use — so a second story is genuinely on the table when the lot supports it.
We render the site plan and run the impervious-cover and FAR calculations against your specific lot before submittal, so the version that lands in front of a reviewer is the version we've already gut-checked.
The Abstract / Cedar Park · Cedar Park, TX.
4. Submittal, fees, activation
The building permit goes through the AB+C Portal's Residential Plan Review web form. Once Residential Intake confirms the submission is complete, they invoice plan review fees; after the plans are approved, permit fees come due and a registered contractor activates the permit. We're your registered contractor, which means activation isn't something you have to chase.
5. Build, inspect, occupy
Active permits expire on day 181 with no inspection, and each passing inspection adds another 180 days. A real build keeps the inspection calendar moving on its own; the permit-expiry trap is something we watch on stalled projects, not active ones. The Certificate of Occupancy issues after the final inspection passes — that's the day the unit is legally inhabitable.
What we handle vs. what stays with you
The short version: we handle every interaction with the City of Austin, and you handle every decision that's genuinely yours.
We handle:property profile + deed-restriction pull, address assignment, site plan and zoning math, GFA / FAR calculations, drainage review (including the modified standards under § 25-7-67 for infill lots created after June 2025), plan submittal, fee invoicing and tracking, reviewer-comment responses, permit activation, the inspection sequence, and the Certificate of Occupancy.
You handle:design choices (which plan, which finishes, which floor on a two-story), financing, deciding whether to lease the unit out long-term, and any conversations with neighbors. We'll surface the trade-offs but the call is yours.
Typical timeline
A simple detached single-story on an SF-3 lot with no deed-restriction wrinkles typically moves from contract to Certificate of Occupancy in roughly six to nine months. Two-story or three-unit projects add review time on the front end and construction time on the back end. Lots with drainage complications under the new infill rules can add a month for the grading-plan compliance step. None of these are surprises — we map the schedule out before the contract is signed and tell you which of those risk factors your lot actually has.
From pre-app to keys
Four phases, every Austin ADU project goes through them. We're on the city-facing side of every one.
Step 01
Pre-app verification
Property Profile, deed restrictions, base zoning, eligible unit count, and any overlay or compatibility wrinkles surfaced before design starts.
Step 02
Site plan & design
Site layout against the 40% building coverage / 45% impervious cover caps, setbacks pulled from the LDC table for your base district, plan selected and tailored.
Step 03
Submittal & review
Residential Plan Review through the AB+C Portal, reviewer comments answered, plan-review fees and permit fees handled, permit activated under our contractor license.
Construction with inspection-cadence-aware scheduling, final inspection passes, Certificate of Occupancy issued — the day your ADU is legally inhabitable.
The questions we hear most often from Austin homeowners about ADU regulations.
How big or how small can my ADU be?
In Austin, adus are limited to 0.15 FAR (ratio of the floor area of your structure as compared to the size of your lot) or 1100 square feet, whichever is smaller. For instance, if you had a 5000sf lot, your adu would be limited to 750 square feet or smaller.
How many stories can my ADU be?
In Austin, all residential structures are limited to 32' in height, as measured from the grade to the midpoint of the roof. In practice, though, they are typically limited to two stories.
How far away from my house does the ADU have to be?
The adu will need to be a minimum of 10'-0" from the main structure.
How close to my property line can the ADU be?
Recently permitted in Austin
Real builds that went through the same permit process described above.
In Austin, the typical side yard setback is 5'-0" and 10'-0" at the rear.
Does an ADU require driveway access?
This depends on where you live. If you are in Austin and live near a transit center (see link below), then you are not required to provide an extra parking space for the adu. If you are required a parking space for the adu, it will need to able to be accessed without someone from the main house having to move their car. http://www.arcgis.com/apps/webappviewer/index.html?id=d7485d285dd24f1ca6bfcfddf01f4771
