# Garage Conversion & ADU in Dripping Springs, TX (2026)

By the Home Remodel Pro team · published 2026-10-18 · Garage Conversion & ADU, Dripping Springs

In Dripping Springs, converting an attached garage into finished living space typically runs $65,000–$115,000, and a detached ADU built from the ground up typically runs $250–$400 per square foot, so a 600–800 sq ft unit lands around $160,000–$320,000. A garage conversion takes about 10–16 weeks of construction; a detached ADU runs about 5–8 months. Below is what moves those numbers, how permitting and septic review work out here, and the sequence we follow from first visit to final walkthrough.

## What a garage conversion costs in Dripping Springs

A garage conversion is priced by what you put inside it, not by the square footage. The shell already exists. The money goes into insulation, conditioned air, electrical, flooring, drywall, windows or doors where the overhead door was, and any plumbing you add.

Here are the ranges we work from. Every one of them becomes a single fixed number in writing before we start.

Attached garages in Dripping Springs are usually two-car, 400–500 sq ft, slab-on-grade, and often a step down from the house floor. That step is one of the most common cost drivers on these jobs — leveling the slab or framing a raised floor adds work, and it affects door heights and the transition into the house.

- Office, gym, playroom or guest suite with no plumbing: $65,000–$85,000. Insulation, drywall, flooring, lighting, conditioned air, infill of the garage door opening, trim and paint.
- Guest suite with a full bathroom: $85,000–$110,000. Adds drain and supply lines cut into the slab, a vent, a tiled shower, and a fixture package.
- Full ADU-style conversion with a kitchenette, bathroom, laundry hookup and a private exterior entry: $100,000–$140,000. Adds cabinetry, counters, appliance circuits, a hood vent and often an electrical panel upgrade.
- Moves the price up: raising or leveling the slab, a new mini-split or an HVAC system that can't carry the extra load, a panel upgrade, septic work, a soundproofed wall between the unit and the house, long trenching runs to a detached garage.
- Moves the price down: keeping the plumbing out of it, keeping the existing garage door opening and infilling with a simple wall and window, standard-height ceilings with no structural changes, finish selections from our standard packages.

## What a detached ADU costs, and what drives it on Hill Country lots

A detached accessory dwelling unit is new construction: foundation, framing, roof, exterior cladding, windows, full mechanical, electrical and plumbing, kitchen, bath and finishes. We price those at roughly $250–$400 per square foot in the Dripping Springs area. A 500 sq ft studio over a slab with a simple roofline sits near the bottom. A 900 sq ft two-bedroom with a porch, standing-seam metal roof and a kitchen built to match the main house sits near the top.

Site work is the variable that surprises people most out here. In-town lots on smaller tracts are usually straightforward. Acreage lots west and south of town bring rock, slope and distance into it:

Utility distance matters more than almost anything else. Running water, sewer or septic line, and a new electrical feed 150 feet to a back corner of the property costs real money in trenching, conduit and rock excavation. If you have a well and septic, both get looked at before the design is finished, not after.

- Rock excavation for the foundation, trenching and any required drainage.
- Slope — a stepped foundation or retaining work adds cost against a flat pad.
- Distance from the main house to the ADU for water, sewer or septic, and power.
- Septic capacity. Adding a dwelling or a bedroom to a tract on an on-site sewage facility usually triggers a review by Hays County and a licensed site evaluator or designer, who determine whether the existing system can serve the addition or whether it needs expansion or replacement. We budget that line item honestly rather than leaving it off the contract.
- Driveway and parking, which some site plan reviews address.
- Whether you want the ADU to match the main house's masonry, roof profile and window style, which costs more than a simple exterior but usually appraises and rents better.

## Permits, septic and inspections around Dripping Springs

Where you sit matters. Some Dripping Springs addresses are inside the city limits, many more are in the extraterritorial jurisdiction or in unincorporated Hays County, and some subdivisions add an HOA architectural review on top. The first thing we do on a garage conversion or ADU is confirm which office reviews your project before we draw anything you'd pay to build.

We handle the permit package — drawings, forms, submittal, review comments and inspection scheduling — the same way we do City of Austin permits. You are not standing in line or chasing a reviewer.

Two items we never guess at. First, whether any wall, header or framing change is acceptable is determined by a licensed engineer and the reviewing office, and when a project needs an engineer's letter or sealed drawings we get them before we submit. Second, whether your tract needs a water-quality or site plan review, and what your septic can carry, is determined by the county and the licensed professionals who evaluate it. Those answers come back in writing during design, not mid-build.

Expect permit and review fees in the range of $1,500–$6,000 for a garage conversion and $3,000–$12,000 for a detached ADU depending on jurisdiction, valuation and whether septic and site plan reviews are part of it. On-site sewage facility permitting and design, when needed, typically adds $1,200–$3,500 before any system work. These are carried as a line in your contract, not a surprise later.

Inspections follow the normal sequence: foundation or slab where applicable, rough framing, rough electrical, plumbing and mechanical, insulation, then final. An inspection that fails on a Friday can cost you a week of calendar, which is why our in-house carpenters stage work so the trades aren't tripping over each other.

## Realistic timeline, first visit to final walkthrough

Design and permitting happen before demolition. That's the whole point — the construction calendar we hand you is the one we build to, because nothing is still being decided when the saws start.

Garage conversion, typical total: 16–24 weeks from first visit to final walkthrough.

Detached ADU, typical total: 8–12 months from first visit to final walkthrough, with 5–8 of those months being construction.

Review times vary by office and by season, and septic design adds weeks when it's in play. We tell you what we're seeing during your design phase rather than quoting a number we can't control. We don't promise a start date before your permit is in hand.

- Weeks 1–2: site visit, measurements, scope conversation, budget range, design agreement.
- Weeks 2–6: drawings, selections (flooring, tile, cabinets, fixtures), engineer or septic designer involvement if your project needs it, then a fixed price in writing.
- Weeks 5–12: permit submittal, review comments, approval. ADUs and anything touching septic sit at the long end.
- Weeks 1–3 of construction: demolition, slab prep, framing, exterior openings, rough electrical and plumbing.
- Weeks 4–7: rough inspections, insulation, drywall, HVAC set.
- Weeks 8–14: cabinets, tile, trim, flooring, paint, fixtures, final inspection, punch list and walkthrough.

## How our fixed-price design-build process works

One contract, one crew, one number. We design it, price it, permit it and build it, and our own carpenters do the framing and trim rather than a rotating cast of subs. That's how the price holds.

The price in your contract is the price you pay. It changes only if you change the scope or if something hidden behind a wall or under a slab has to be corrected — and if that happens, you see the cost and sign off before we proceed. Workmanship carries a 5-year warranty. Financing is available if you'd rather not pull the whole project out of cash.

If you're interviewing contractors for a Dripping Springs garage conversion or ADU, ask these:

- Is this a fixed price or an estimate? Get the answer in writing.
- Which office reviews my project — the city, the county, or both — and who submits the package?
- Does my septic need review or expansion for this, and who is the licensed designer evaluating it?
- Is an engineer involved, and is that fee in the contract or added later?
- Who does the framing and trim — your employees or a sub you met last month?
- What is the allowance for tile, cabinets and fixtures, and what happens if I pick something above it?
- What does the workmanship warranty cover, and for how long?
- How do change orders get priced and approved?

## What to do next

Before you call anyone, gather three things: your plat or survey if you have it, your septic permit and system records if you're not on city sewer, and your HOA's architectural guidelines if your neighborhood has them. Those three documents answer most of the questions that otherwise stall a project for a month.

Then decide what the space is actually for. A home office and a rentable ADU look similar on a floor plan and are $40,000 apart in reality, because one needs a kitchen, a bathroom, a private entrance and its own climate control. Being honest about that on day one keeps the design from being redrawn twice.

Book a site visit with Home Remodel Pro. We'll walk the garage or the proposed ADU site, talk through what your lot and your utilities will support, and give you a realistic range the same day. If the numbers work for you, we move into design, and you get a fixed price in writing before anything gets torn out.

## Dripping Springs homeowners also ask

### Can I rent out an ADU in Dripping Springs?

Whether a unit can be rented, and under what terms, depends on your jurisdiction and your HOA — the city or county and your neighborhood's recorded rules determine that, not your contractor. We confirm which office reviews your property during design and build the unit to what that review approves. If rental income is the goal, tell us on the first visit, because it affects the entry, parking, laundry and sound separation we design in.

### Does converting my garage mean I lose my parking?

Usually, yes — that's the trade. Some Dripping Springs lots have room to add a carport or a detached garage later, and some site plan reviews address on-site parking. On acreage lots this is rarely an issue; in tighter subdivisions it's worth confirming with the reviewing office before design, which we do as part of the permit package.

### Will an ADU work on my well and septic?

That gets answered by Hays County and a licensed site evaluator or septic designer, who review your existing system and your soils. It's one of the first things we line up, because the answer changes both the budget and the schedule. Septic design and permitting typically add $1,200–$3,500 before any system work, and system expansion, if it's needed, is carried as its own line in your fixed-price contract.

### How much of the cost is design and permitting?

On a garage conversion, design, drawings, engineering where needed, and permit fees typically total $5,000–$12,000. On a detached ADU, expect $12,000–$30,000 depending on size, whether sealed drawings and septic design are involved, and which office reviews it. All of it is itemized in the fixed price you sign before demolition.

## Check it with Dripping Springs's own pages

Permit rules and fees change, and the office that issues the permit is the authority on them, not this guide.

- [City of Dripping Springs — building permit information](https://www.drippingspringstx.gov/329/Building-Permit-Information)
- [City of Dripping Springs — outdoor lighting](https://www.drippingspringstx.gov/325/Lighting)

What a garage conversion or ADU in Austin involves: https://www.homeremodelpro.com/austin/garage-conversion-adu

## Get a free estimate

- Call (512) 601-5666 (Monday to Friday 8am–6pm and Saturday 9am–2pm); a project consultant calls back within one business hour.
- Request an estimate online: https://www.homeremodelpro.com/austin#quote
- 5-year workmanship warranty · one fixed price in writing · in-house carpenters · permits and inspections included

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Source: https://www.homeremodelpro.com/austin/blog/garage-conversion-and-adu-dripping-springs-guide · Home Remodel Pro Austin, TX