Building on Your Own Lot in the Highland Lakes: Costs, Permits, and What to Check Before You Buy

Many of the best homes around Marble Falls, Burnet, Horseshoe Bay and Lake LBJ start the same way. Someone finds a piece of land they love, then works out how to build on it.

That order makes sense. The land is what makes these homes worth building. But two lots a mile apart can differ in cost by six figures before the foundation is poured, because of rock, slope, septic, water and access. None of that shows up on a listing.

This guide covers what we look at on every lot before design begins. It's based on how permitting and site work actually go in Burnet County, Llano County and the Highland Lakes. Use it to check a property before you close, or to plan the next step on land you already own.

Before You Buy: The Lot Checklist

If you only read one section, read this one. Each item can change your budget, where the house can sit, or whether the lot works at all.

• Survey and legal description: current boundaries, easements and setbacks.

• Deed restrictions and HOA rules: minimum square footage, materials, roof types, setbacks, and whether plans need architectural committee approval.

• Floodplain status: in Burnet County this changes the building permit class and cost.

• Septic jurisdiction: the county or the LCRA, depending on how close you are to the lakes.

• Septic feasibility: what type of system the soil will support, and where it can go.

• Water source: city water, a water supply corporation, or a private well, and whether a well is allowed on the tract size.

• Rock and slope: how much excavation, retaining wall and foundation engineering the site will need.

• Access: driveway length, grade, and the cost of a culvert or road cut.

• Electric and internet: distance to the nearest power service, and whether fiber is available.

• Views and orientation: where the house should face, and what the sun and wind will do on the site.

We review these items with buyers before they close, and you're welcome to contact us about a property you're considering. We don't charge for a pre-purchase lot review. Our fees begin when construction begins, unless we're designing your plans, handling permitting, and preparing engineering and structural plans in advance so you're ready to build.

Septic: Who Permits It and Why It Shapes the House

Most Highland Lakes lots outside city sewer service use an on-site sewage facility (OSSF), usually called a septic system. Three things matter: who issues the permit, what system the soil allows, and where the system has to go.

County or LCRA?

Near the lakes, the permitting authority may not be the county. The Lower Colorado River Authority regulates septic systems within a 2,200-foot zone around the upper Highland Lakes and a 2,000-foot zone around Lake Travis. That covers much of the shoreline around Lake LBJ, Lake Marble Falls, Inks Lake and Lake Buchanan.

Don't guess from a lake view or a mailing address. Enter the property address in LCRA's jurisdiction map to see which office applies.

Burnet County

In unincorporated Burnet County, the order of steps matters. The county requires:

1. a 911 address first,

2. then a building permit, which is $25 outside a flood hazard area or $400 inside one with an elevation certificate or engineer's letter,

3. then the septic permit, which is $250 for most systems and $400 for an aerobic system.

The county will not process incomplete applications. Burnet County also permits and inspects every septic system regardless of tract size, so the state's 10-acre exemption doesn't help you there.

Llano County

Llano County requires a Development Permit for every structure built or substantially modified in the county. That applies even where the LCRA handles septic, or where sewer is available. Applications go through the county's Development Services portal, which says to allow 7–10 business days for non-floodplain reviews. Floodplain and septic reviews take longer.

Why the soil test comes first

Every septic permit starts with a site evaluation by a licensed site evaluator or engineer. Under LCRA rules, if the evaluation finds unsuitable soil, groundwater, or a restrictive layer less than two feet below the planned drain field, a conventional system can't be used. On shallow Hill Country rock, that often means an aerobic or engineered system, which costs more and comes with maintenance requirements. LCRA, for example, requires a maintenance contract for the first two years.

The drain field or spray area also takes up a lot of your lot. It has to stay clear of the house, the well, the driveway and the pool. On smaller or steep lots, the septic layout often decides where the house can go, not the other way around. That's why we get the soil evaluation done before the floor plan is final.

Water: City, Supply Corporation, or Well

If the lot is outside a city or water supply corporation's service area, you'll need a well.

In Burnet County, wells are regulated by the Central Texas Groundwater Conservation District. Every new well must be registered and receive specific authorization before drilling starts. Minimum tract sizes depend on the aquifer: two acres for most of the Trinity Aquifer, one acre for other aquifers, and 10 acres inside the Northeast Burnet County Trinity management zone created in 2026. If you're buying a small tract and planning to drill, confirm this before you close.

Waterfront owners who want to pump lake water for irrigation need a separate agreement. LCRA requires a Domestic Use water contract to draw from the Highland Lakes.

Rock, Slope, and Foundations

The views that make Hill Country lots valuable usually come with elevation changes, and the ground under them is often limestone or granite close to the surface. Both affect:

• how much excavation the site needs, and whether rock has to be hammered or sawed out,

• foundation design, including engineered slabs, piers, or stem walls on steep sites,

• retaining walls and drainage,

• how a pool, a walk-out lower level or a garage can be set into the slope.

We cover this in detail in Building on Sloped Terrain in the Texas Hill Country. The short version: on a sloped lot, the foundation and site work can cost as much as a lower-level room addition, so it needs to be in the budget from day one.

Driveways, Electric, and Utility Runs

These costs catch many buyers off guard because a listing never shows them:

• Driveway: a few hundred feet of rock driveway is very different from a long, steep approach that needs base, drainage and possibly paving.

• Electric service: around the Highland Lakes, that's usually Pedernales Electric Cooperative (PEC) or Central Texas Electric Cooperative (CTEC). The cost depends on distance, whether a transformer is already on the property, and whether service runs overhead or underground.

• Internet: fiber availability varies widely across Burnet and Llano counties. Some lots need fixed wireless or satellite.

• Propane: many rural homes use propane for cooking, water heating or generators, which means planning where the tank goes.

Permits by Location

Who you permit through depends on exactly where the lot sits.

• City of Marble Falls — Building permit: City Development Services: plan review $100–$150; new construction $0.50/sq ft plus 10% per trade; Septic: City sewer or OSSF; Notes: Plans reviewed against the city's 2024 adopted codes

• City of Burnet — Building permit: City of Burnet; Septic: City sewer or OSSF; Notes: Generally quick turnaround in our experience

• Unincorporated Burnet County — Building permit: Burnet County ($25 / $400 flood zone); Septic: Burnet County or LCRA; Notes: 911 address first; septic permit required on every tract

• Unincorporated Llano County (incl. Kingsland, Lake LBJ areas) — Building permit: Llano County Development Permit; Septic: Llano County or LCRA; Notes: Development Permit required even where LCRA handles septic

• City of Horseshoe Bay — Building permit: City Development Services; Septic: County-approved OSSF or city service; Notes: Architectural Control Committee approval comes before the city permit

In Horseshoe Bay, the new-home permit checklist also requires:

• a recorded plat,

• a 911 address,

• a tree survey by a certified surveyor,

• an LCRA erosion-control site plan,

• stamped structural plans,

• the approved septic package (where septic applies).

Larger projects anywhere in the watershed may also fall under the LCRA's Highland Lakes Watershed Ordinance. It requires a development permit when impervious cover exceeds 10,000 square feet or more than an acre of land is disturbed. Marble Falls, Burnet and Horseshoe Bay administer parts of that ordinance locally.

In our experience, Burnet, Llano and Blanco counties are easy to work with and turn permits around quickly. Waterfront lots are the exception. LCRA review, from erosion-control (ESC) plans to septic approval, can be a lengthy process when the septic system is within 200 feet of the water, so build that time into your schedule.

Permit fees and codes change, so check with the issuing office before you apply.

What Site Work Typically Costs

Every lot is different, which is why we evaluate the property before giving a budget. These are the ranges we're seeing on recent Highland Lakes projects:

• Septic, conventional system: $9,500–$12,000

• Septic, aerobic or engineered system: About $13,500

• Water well, drilled and pumped: $15,000–$32,000, depending on depth. About $15,000 for a 200-foot well; a recent 720-foot well ran about $32,000.

• Driveway: About $5 per linear foot for rock base; ribbon curbs about $25 per linear foot

• Electric service extension: Roughly $2,000 per pole, with a pole about every 250 feet. Varies by provider (PEC or CTEC), whether a transformer is already on the property, and overhead vs. underground. PEC won't estimate until an application is submitted and the design request is in their queue.

• Excavation and site prep on sloped lots: About $20,000 on our average sloped lot, usually a combination of rock chipping and leveling, paired with concrete or limestone block retaining walls. Depends on the slope and whether it's dirt or rock.

• Retaining walls: Depends on height, length, and whether the wall is structural. 2' × 5' limestone blocks run about $130 each, and setting them costs about the same again, so a 20-block wall typically runs around $5,000. We waterproof our walls and add PVC drainage for safety and longevity.

These costs are on top of the home itself. Our homes generally range from $250 to $800 per square foot depending on build level, foundation and lot slope, and selections. A flat lot with city water and sewer and a steep lot with an aerobic septic system and a 600-foot driveway are two very different projects, even with the same floor plan.

For why budgets go off track early, see Why Most Custom Home Budgets Blow Up Before Construction Starts.

How Long It Takes

• Lot evaluation, survey and soil testing: a few weeks.

• Design, engineering and permitting: at least three months, and up to six in some jurisdictions depending on their permit queue. Septic permits alone can take up to 30 days once a complete application is in. HOA or architectural committee review adds time where it applies.

• Construction: our average is 10 months from groundbreaking to move-in. Depending on the size and complexity of the home, it ranges from about 8 months to 2 years.

How We Handle Build-on-Your-Lot Projects

As a design-build firm, we handle the land, the design and the budget together, so the house is designed around what the lot actually requires. We also work with several bank partners, so we can take care of every step for you:

1. Client Questionnaire: tell us about your lot, budget and goals.

2. Site evaluation: survey, soil and septic feasibility, water, access, utilities, rock and slope.

3. Design and budget: floor plan, elevations and a line-item budget that includes the site work, before construction starts.

4. Permitting: we coordinate the county or city, the LCRA, and any architectural committee.

5. Build: cost-plus construction with transparent draw requests. See how a true cost-plus contract works.

Where We Build on Client-Owned Land

We build on client-owned lots throughout the Highland Lakes and the surrounding Hill Country:

• Burnet: acreage, ranch and golf course homes. Our Park Road 4 home sits near Longhorn Caverns.

• Burnet County: rural acreage across the county.

• Marble Falls: in-town lots, lake lots and hillside acreage.

• Horseshoe Bay: waterfront, golf course and hillside lots with architectural committee review.

• Lake LBJ: including our Lighthouse Golf Course home in Kingsland.

• Llano, Spicewood, Lampasas, Round Mountain and Johnson City.

Frequently Asked Questions

Can you evaluate a lot before I buy it?

Yes, and we don't charge for it. We look at septic feasibility, water, access, utilities, rock, slope and restrictions, so you know what the site will require before you close. Our fees begin when construction begins, unless we're preparing your design, permitting and engineering in advance.

Do I need a septic permit on 10 acres or more?

In Burnet County and Llano County, yes. Both counties permit and inspect every system regardless of tract size. Within LCRA's jurisdiction near the lakes, the LCRA permit applies.

How do I know whether the county or the LCRA permits my septic system?

Enter the address in LCRA's OSSF jurisdiction map. If the property is near the boundary, LCRA will make the determination.

Can I drill a well on a small tract in Burnet County?

It depends on the aquifer and the tract size. Most of the Trinity Aquifer requires at least two acres per well, other aquifers one acre, and the Northeast Burnet County Trinity zone 10 acres. Every new well must be registered and authorized before drilling.

Do you build from my plans or yours?

Either. We can start from one of our floor plans, design from scratch, or price and build plans you already have.

How much does it cost to build on my own lot?

The home itself generally runs $250–$800 per square foot depending on build level and selections, plus site costs that depend on the lot. A site evaluation is the only way to get a reliable number.

Start With the Land

If you own land in the Highland Lakes, or have your eye on a property, the best time to talk to a builder is before the design is set and ideally before you close.

Start the Client Questionnaire or call 512-900-0841.

Current Custom Homes · 303 Main Street, Suite 6, Marble Falls, TX 78654