A larger lot can create exciting possibilities.

You may picture a casita for visiting relatives, a quiet detached office, a workshop for hobbies, or an RV garage that finally gets a motorhome out of the driveway. Buyers looking in Garden Ridge and the surrounding Hill Country often place these possibilities high on their wish lists.

But “there appears to be plenty of room” is not the same as “the structure is allowed.”

A one-acre property may have fewer usable building options than a smaller, better-positioned lot. Setbacks, easements, private restrictions, septic components, drainage paths, trees, utilities, and zoning classifications can all reduce the area that can actually be developed.

Before buying plans—or buying the property itself—it is important to answer a more detailed question:

Can this specific structure, for this specific use, be built in this specific location on the lot?

Can You Build Another Structure on Your Property?

Possibly, but the answer usually depends on four separate approval layers:

1. Municipal, county, or extraterritorial-jurisdiction requirements
2. Recorded plats, easements, deed restrictions, and HOA rules
3. Utility, septic, drainage, floodplain, and site conditions
4. The intended use of the structure

A city may allow an accessory building while the subdivision restrictions prohibit it. An HOA may approve the exterior design while the proposed location violates a utility easement. A detached garage may meet zoning rules but become an accessory dwelling unit once a kitchen, bathroom, and sleeping area are added.

A property is not confirmed buildable for an additional structure until all applicable layers have been reviewed.

What Are You Actually Planning to Build?

The terminology matters because different structures are often regulated differently.

Casita or accessory dwelling unit

A casita is commonly treated as an accessory dwelling unit, or ADU, when it functions as a separate living space. It may include:

• A private entrance
• Sleeping space
• A full bathroom
• Cooking facilities
• Heating and cooling
• Separate or shared utilities

Other commonly used names include guest house, garage apartment, carriage house, in-law suite, and secondary dwelling.

The name used in a real estate listing does not determine the legal classification. The structure’s design and use usually matter more.

Guest quarters

Some local codes distinguish guest quarters from an independent dwelling. Guest quarters may be intended for temporary visitors and may not be permitted to include a complete kitchen or operate as a separately rented residence.

Cibolo’s posted 2024 Unified Development Code illustrates this distinction. It defines accessory living quarters as temporary guest accommodations without kitchen facilities and not rented as a separate dwelling. It separately defines an accessory residential unit as owner-occupied space within the principal use, limited to one-third of its gross floor area and requiring an additional off-street parking space. Whether the use is permitted or conditional depends on the zoning district.

Workshop or storage building

A workshop is generally an accessory structure when it remains secondary to the main residence. Depending on the jurisdiction, its use may also be limited to personal activities rather than a business that generates employees, customers, deliveries, noise, or outdoor storage.

Adding plumbing does not automatically make a workshop a dwelling. Adding a kitchen, bathroom, sleeping accommodations, or separate residential occupancy may change how the project is reviewed.

RV garage or RV port

An RV garage is normally treated as an accessory garage or building, but its height, door size, driveway access, lot coverage, exterior materials, and placement may create additional design issues.

Garden Ridge’s zoning definitions specifically include private garages, carports, RV ports, tool houses, and home workshops as examples of accessory structures.

A true second dwelling

A second principal residence is not always the same as an accessory dwelling. A second principal home may require different zoning, minimum lot area, subdivision approval, utility arrangements, addressing, fire access, or platting.

Calling a building a “casita” will not make it accessory if its size, use, or configuration causes the governing authority to classify it as another principal dwelling.

What Do Garden Ridge’s Rules Say?

Garden Ridge offers a useful example of why property-specific research matters.

Under the city’s zoning ordinance, no more than one accessory dwelling may be located on a lot. The ordinance states that it may be occupied by a guest, caregiver, relative, or family member; must meet the setbacks that apply to the principal dwelling; and may not exceed 50% of the principal dwelling’s living area. The principal home must also be occupied by the owner or an authorized lessee.

Garden Ridge also regulates the combined number and size of residential accessory structures:

• Lots smaller than three-quarters of an acre may have up to two accessory structures with no more than 1,000 square feet of combined floor area.
• Lots of three-quarters of an acre or more may have up to three accessory structures with no more than 3,000 square feet of combined floor area.
• Accessory structures must be behind the front façade of the primary dwelling.
• Side and rear setbacks are the same as those required for the primary dwelling under the property’s zoning.
• Structures cannot be placed inside easements or setbacks.
• Buildings of 300 square feet or more must satisfy applicable exterior-material and design requirements.

This means a larger Garden Ridge lot may provide more accessory-building capacity, but acreage alone still does not answer the question. Existing garages, sheds, pool structures, setbacks, and easements may already use part of the permitted space.

The regulations also do not automatically establish that an accessory dwelling can be separately rented or used for a particular commercial purpose. The proposed occupancy and use should be confirmed directly with the city.

What About Casitas in San Antonio?

The City of San Antonio currently allows one ADU on properties in designated residential zoning districts, subject to owner-occupancy and development requirements. The owner must live in either the main residence or the ADU; a property without an owner living on-site generally must be rezoned to allow more than one dwelling unit.

San Antonio’s current ADU guidance states that:

• Only one ADU is permitted on a qualifying property.
• An ADU may be up to 800 square feet or 50% of the main house’s size, whichever is larger.
• The ADU cannot exceed 1,600 square feet.
• Detached ADUs are limited to two stories and 25 feet in height.
• Separate utilities may be possible.
• The owner-occupancy affidavit and covenant must be recorded in Bexar County’s public records.

The applicable zoning district, location on the lot, setbacks, parking, historic-district requirements, floodplain conditions, and construction codes still need to be reviewed for the individual property.

Do Schertz, Cibolo, and New Braunfels Use the Same Rules?

No. Nearby cities may use similar terms but apply different definitions, size limitations, permit thresholds, and approval procedures.

Schertz defines an accessory dwelling unit as a residential dwelling on the same lot as a single-family residence, either inside the primary building or in a detached unit or building. The city also states that sheds and accessory buildings larger than 120 square feet require a permit, and structures on permanent foundations may require additional foundation or flatwork permitting.

As discussed above, Cibolo distinguishes between guest quarters without a kitchen and owner-occupied accessory residential space. Its use table varies by zoning district, meaning a project may be permitted in one district and conditional in another.

New Braunfels provides residential permit categories for accessory buildings, garages, carports, foundations, driveways, plumbing, electrical work, and floodplain development. That is a good reminder that a single backyard project may require several coordinated permits rather than one general approval.

Never carry one city’s casita or accessory-building rules into a neighboring community.

Does an HOA or Deed Restriction Have the Final Say?

Private property restrictions must be reviewed separately from government regulations.

A city permit does not necessarily eliminate an owner’s obligation to comply with:

• Recorded deed restrictions
• Subdivision covenants
• Architectural-control requirements
• HOA design standards
• Minimum or maximum building sizes
• Masonry or roofing requirements
• Limits on detached garages or guest houses
• Restrictions on rental or business use
• Screening and placement rules

Texas law recognizes restrictive covenants contained in dedicatory instruments, and local ordinances may expressly preserve the effect of easements and private agreements. Garden Ridge’s zoning ordinance, for example, states that its provisions are not intended to eliminate an easement, covenant, or other private agreement.

Government approval and private approval are two different questions. A responsible feasibility review should answer both.

Why Are the Survey, Plat, and Easements So Important?

A survey helps establish what portion of the lot may actually be available.

The review should identify:

• Property boundaries
• Building setback lines
• Utility easements
• Drainage easements
• Access easements
• Existing encroachments
• Septic tanks and drain fields
• Wells and required separation areas
• Overhead and underground utilities
• Existing accessory structures
• Impervious-cover limitations
• Floodplain or drainage areas

A wide backyard can contain a substantial utility or drainage easement. Even when an easement is not visibly being used, permanent construction may still be prohibited within it.

Older surveys should also be compared with current site conditions. A shed, pool, fence, driveway, or addition constructed after the survey date may not appear on the document.

What If the Property Uses a Septic System?

A second dwelling can increase the anticipated wastewater load, and an existing septic system may not have been designed or permitted for it.

The Texas Commission on Environmental Quality advises applicants to submit planning materials to the appropriate OSSF permitting authority and arrange for a site evaluation by a licensed site evaluator or professional engineer. The evaluation may include the full lot, soil conditions, the proposed disposal area, and other criteria needed to determine whether a system is suitable.

Questions to investigate include:

• Is the current system properly permitted?
• What number of bedrooms or expected flow was it designed to serve?
• Can the existing system support the additional use?
• Is an expansion or replacement required?
• Is there enough undisturbed land for the disposal and replacement areas?
• Will the proposed building, driveway, or foundation interfere with septic components?
• Which city, county, public-health district, or TCEQ office is the permitting authority?

This can be especially important on acreage and semi-rural properties around Garden Ridge, Bulverde, Spring Branch, New Braunfels, and the surrounding Hill Country.

What Other Site Conditions Can Affect the Project?

Floodplain and drainage

A structure that fits within the zoning envelope may still require floodplain review, elevation documentation, engineered drainage, or a floodplain development permit.

FEMA identifies its Map Service Center and National Flood Hazard Layer Viewer as the official starting points for reviewing effective flood-hazard information. A map review is useful, but it should not replace a survey, elevation work, drainage study, or local floodplain determination when the site presents concerns.

Trees and natural features

Protected trees, critical root zones, steep grades, rock outcroppings, and natural drainage paths can affect both the location and cost of construction. A technically buildable area may not be the most responsible or economical place to build.

Utilities

The project may require evaluation of:

• Electrical-service capacity
• Water availability
• Sewer or septic connections
• Gas or propane service
• Utility trench routes
• Separate metering
• Impact or tap fees
• Address assignment
• Fire access

Separate meters may be possible in some jurisdictions, but they should not be assumed before the utility providers and permitting authority review the plans.

Driveway and access

An RV garage may need more turning room, a wider driveway, a stronger driveway surface, or a modified curb approach. New access points onto public roads may require a separate permit.

How Much Does a Casita, Workshop, or RV Garage Cost?

There is no dependable universal price per square foot for these projects.

Two buildings with the same floor area can have very different total costs because of:

• Foundation and excavation requirements
• Rock and soil conditions
• Utility distance
• Septic modifications
• Drainage engineering
• Retaining walls
• Driveway construction
• Exterior-material requirements
• Kitchen and bathroom finishes
• HVAC systems
• RV-height walls and doors
• Architectural and engineering plans
• Permit, utility, and review fees

Before comparing contractor bids, make sure each bid includes the same site work, utilities, permits, engineering, finish level, and exclusions.

A low initial building estimate may not include the work necessary to make the structure legal and usable.

Will the Improvement Increase the Property’s Value?

It may, but not necessarily by the full cost of construction.

A well-designed, properly permitted casita, workshop, or RV garage can make a property more useful and appealing to certain buyers. The market contribution will depend on factors such as:

• Quality and condition
• Legal and permitted status
• Compatibility with the main home
• Utility and access arrangements
• How common the feature is in competing properties
• Whether comparable sales support an adjustment
• The structure’s flexibility for future owners

Highly specialized buildings may be valuable to a narrower group of buyers. A large workshop that is ideal for one owner may use yard space that another buyer would prefer to keep open.

Before building solely for resale, ask a local real estate professional to evaluate comparable properties with similar improvements. Appraisal value, buyer appeal, construction cost, and personal usefulness are related—but they are not the same measurement.

What Should Buyers Verify Before Purchasing a Property?

Buyers should begin the review during the contract period whenever the ability to construct another building is important to the purchase.

A practical investigation may include:

1. Confirming whether the property is inside a city, county, ETJ, or special district.
2. Identifying the zoning district and allowed use.
3. Obtaining the recorded plat, current survey, deed restrictions, and HOA documents.
4. Reviewing setbacks, easements, lot coverage, height, and accessory-structure limits.
5. Asking the planning department how it would classify the intended structure.
6. Preparing a preliminary site plan showing dimensions and placement.
7. Checking floodplain, drainage, trees, slopes, and utility routes.
8. Evaluating sewer or septic capacity.
9. Obtaining preliminary contractor, architect, engineer, and utility feedback.
10. Confirming that financing and insurance will accommodate the project.

Whenever possible, obtain written responses rather than relying only on an informal phone conversation.

The best time to discover a property cannot support the planned structure is before the purchase—not after closing.

What Should Sellers Verify Before Marketing Extra Buildings?

Sellers should avoid describing a detached building as a legal dwelling, apartment, rental unit, or additional living area without appropriate support.

Before marketing the improvement, gather:

• Building and trade permits
• Certificates of occupancy when applicable
• Approved plans
• Septic documentation
• Survey information
• Utility records
• HOA or architectural approvals
• Relevant repair and construction receipts

An attractive finished space may still create concerns for a buyer, lender, insurer, or appraiser if its permitted status or authorized use is unclear.

Clear documentation can help buyers understand what the structure is—and what it is not.

The Bottom Line

You may be able to add a casita, workshop, RV garage, or second dwelling in Garden Ridge or the surrounding San Antonio area. The answer, however, cannot be determined by acreage or backyard appearance alone.

The most reliable path is to review the intended use, zoning, setbacks, existing structures, plat, survey, easements, private restrictions, utilities, septic capacity, drainage, floodplain conditions, and permit requirements together.

A property with verified expansion potential can offer meaningful flexibility. A property purchased on assumptions can create expensive limitations.

How Correa Realty Group Can Help

When an additional dwelling, workshop, or RV garage is part of your property plan, Correa Realty Group can help you investigate that goal before you make a major decision.

Our role may include:

• Helping identify properties with appropriate lot size and layout
• Reviewing available surveys, plats, seller disclosures, and property documents
• Helping you recognize questions that should be directed to the city, county, HOA, title company, utility provider, or septic professional
• Comparing homes that already have permitted accessory buildings
• Evaluating how similar improvements have been received in the local resale market
• Helping structure a purchase timeline that allows meaningful due diligence
• Connecting the investigation with qualified surveyors, contractors, engineers, lenders, inspectors, insurers, attorneys, and other professionals when appropriate

We do not replace the governing authority, surveyor, engineer, attorney, or contractor. We help clients ask better questions, organize the information, and understand how the findings may affect a real estate decision.

Correa Realty Group serves Garden Ridge, San Antonio, New Braunfels, Schertz, Cibolo, and surrounding Hill Country communities.

Considering a property because of its casita, workshop, or RV-garage potential? Contact Correa Realty Group for thoughtful local guidance before relying on the available space alone.

FAQs

Can I build a casita on my property in Texas?

You may be able to build a casita, but Texas does not have one universal rule that makes every residential lot eligible. The answer depends on the city or county jurisdiction, zoning district, setbacks, lot coverage, easements, deed restrictions, utilities, septic capacity, floodplain conditions, and the casita’s size and use. A structure with a kitchen, bathroom, and independent living facilities may be classified differently from guest quarters without a kitchen. Confirm the classification and requirements before purchasing plans or beginning construction.

Can I build a casita in Garden Ridge?

Garden Ridge allows one accessory dwelling per lot when the city’s requirements are satisfied. Its living area cannot exceed 50% of the principal home’s living area, it must meet the primary dwelling’s setbacks, and the principal dwelling must be occupied by the owner or an authorized lessee. Garden Ridge also limits the number and combined size of accessory structures based partly on whether the lot is smaller than three-quarters of an acre. Deed restrictions and existing structures must still be reviewed separately.

How large can an accessory dwelling unit be in San Antonio?

A qualifying San Antonio ADU may be up to 800 square feet or 50% of the main house’s size, whichever is larger, but cannot exceed 1,600 square feet under the city’s current guidance. Only one ADU is permitted on a qualifying property, and the owner must live in the main home or the ADU unless the property is rezoned for more than one dwelling. Zoning, setbacks, height, floodplain conditions, parking, and recorded owner-occupancy documents must also be addressed.

Is a workshop or RV garage considered a second dwelling?

No, not when it is designed and used only as an accessory workshop, garage, or storage building. The classification may change when independent living features are added, especially a kitchen, full bathroom, sleeping accommodations, and separate residential occupancy. A large RV garage may also face different height, driveway, exterior-design, and lot-coverage requirements than a smaller shed. Ask the planning department to classify the complete proposed design rather than describing it only as a “shop” or “garage.”

Can my HOA prevent me from building a casita even if the city allows it?

Yes, private restrictions may be more limiting than the city’s basic zoning allowance. Recorded covenants or HOA rules may regulate detached buildings, exterior materials, rooflines, minimum size, maximum height, placement, rental activity, or architectural approval. A city permit does not necessarily waive those private obligations. Review the recorded deed restrictions, amendments, subdivision plat, and architectural-control procedures before assuming the project is permitted. Legal questions about enforceability or conflicting documents should be directed to a qualified Texas real estate attorney.

How much value does a casita or RV garage add?

The improvement may add market value, but the increase is not guaranteed to equal the construction cost. Value depends on permitted status, quality, utility, condition, neighborhood expectations, available comparable sales, and demand among likely buyers. A flexible casita may appeal to a wider audience than a highly specialized workshop, while an RV garage may be especially attractive on larger Hill Country properties. Before building for resale, request a market review of comparable properties and discuss potential appraisal treatment with a qualified appraiser or lender.

When should I investigate whether I can add another building?

Investigate before purchasing the property or paying for detailed construction plans. Buyers should use the contract and due-diligence period to obtain the survey, plat, deed restrictions, zoning information, septic records, flood data, and preliminary feedback from the applicable authorities. A basic site plan can help the city, HOA, contractor, surveyor, and utility providers give more meaningful answers. Starting early also allows time to determine whether a variance, conditional-use approval, septic redesign, or other extended process could be required.

Can an existing septic system support a second dwelling?

Not automatically. The system may have been designed for only the main home’s approved bedroom count or wastewater flow. Adding another living unit could require a professional site evaluation, revised planning materials, system expansion, or replacement. The proposed structure and driveway must also avoid septic tanks, treatment components, disposal areas, and required replacement areas. TCEQ recommends working through the appropriate local permitting authority and using a licensed site evaluator or professional engineer when preparing OSSF planning materials.

When can a real estate agent help with a casita or workshop decision?

A locally experienced real estate agent can help when the improvement affects which property you buy, how much you offer, what documents you request, or how you evaluate future resale. The agent can help organize surveys, plats, restrictions, seller records, zoning questions, and comparable-property information while coordinating with the specialists who make technical or legal determinations. This is especially useful when comparing an undeveloped lot with a property that already has a permitted casita, workshop, or RV garage.