How much does a building permit cost in unincorporated Trinity County, TX?

The minimum permit fee is $5. Fees are calculated as: Flat fees. OSSF: Residential standard $325, residential multi-family $325, commercial/business $450, each additional RV at business sites $50, maintenance reports and contracts $5, affidavit aerobic or 10 acre exemption $25. Subdivision: major $750 initial and $750 approved, rural subdivision with road $750 initial and $750 approved, minor subdivision $500 initial and $500 approved, replat $250 plus posting/publishing initially and $250 on approval, recording of approved plat $250.. Plan check fee: Minor subdivision $3,000, rural subdivision with road $5,000, major subdivision $6,000, RV park $5,000, or amount set in consultation with engineer for exceptional situations.

What work is exempt from building permits in unincorporated Trinity County, TX?

The following work is generally exempt: OSSF work may qualify for state-law exemptions when statutory conditions are met, such as the Ten Acre Exemption affidavit. Note: No public county exempt-work list for general building work because no public countywide general building-permit program was found. For heavy-haul activity, the county publishes a Heavy Haul Permit form through the Commissioners forms page rather than an exemption list.

County Building Permits

Trinity County, TX - 2026 Building Permit Guide

How to apply for a building permit in unincorporated Trinity County, Texas. Permit authority, application steps, fees, and inspection requirements.

Texas Updated March 2026

Permit Authority

Unincorporated Trinity County only, outside Groveton and Trinity city limits. County controls include OSSF/septic permits, subdivision and platting, heavy-haul use of county roads, and county addressing. Parcel-level city-limit verification remains important near municipal boundaries.

Department: Trinity County (County Judge's Office, Commissioners Court, Commissioners' Office, 911 Addressing and GIS Mapping)
Address: Trinity County Courthouse, 162 West 1st St, Groveton, TX 75845
Phone: 936-642-1746 (County Judge's Office and OSSF); 936-642-2743 (Commissioners); 936-642-3904 (911 Addressing)
Email: 911map@co.trinity.tx.us
Website: https://www.co.trinity.tx.us/

Online Permit Portal

Open Trinity County Environment and Septic

Platform: Trinity County website plus CIRA-hosted pages for OSSF • Account required: No • Submission: In-person only

Additional resources:

Application Process

Determine whether the project falls into one of the county's published approval programs (OSSF, subdivision, heavy-haul, or addressing).
For OSSF and septic work, contact the County Judge's Office to obtain the permit application and packet.
Obtain a site evaluation from a licensed site evaluator and a septic design from a Texas licensed professional engineer or registered sanitarian, then submit those items with the permit application.
If the system uses secondary treatment (aerobic), provide the required affidavit to the public, maintenance agreement, and recorded documents before final operation approval.
Wait for county review. If compliant, the county issues an Authorization to Construct.
Request inspections before any lines or tanks are covered and at least two days before installation unless waived by the assigned designated representative.
For subdivision projects, follow county subdivision regulations and pay listed development and engineering-review fees.
For heavy-haul use on county roads, submit the permit through the Commissioners forms page before hauling begins.

Source: Trinity County (County Judge's Office, Commissioners Court, Commissioners' Office, 911 Addressing and GIS Mapping)

General Requirements

No public countywide general building permit program was found for ordinary building construction in unincorporated Trinity County. Published county permit and approval controls include: OSSF and septic permits, subdivision and plat approval under county subdivision regulations, heavy-haul permits for county roads, and 911 address assignment and GIS coordination.

Required Documents

For OSSF: application, site evaluation report, system design, and for aerobic systems the affidavit to the public and maintenance agreement
For subdivision: plans and plat per subdivision regulations
For heavy-haul: county heavy-haul permit request

Building code: No public countywide building-code adoption or general county building-code enforcement program was found.
Owner-builder: For OSSF, any person other than the homeowner who installs a system must hold the required state installer license.
Contractor requirements: For OSSF: designs must come from a Texas licensed professional engineer or registered sanitarian; site evaluations must be performed by a licensed site evaluator; non-owner installers must be licensed by the State of Texas as Installer 1 or Installer 2 depending on the system.

Fees

Minimum permit fee: $5
Plan check fee: Minor subdivision $3,000, rural subdivision with road $5,000, major subdivision $6,000, RV park $5,000, or amount set in consultation with engineer for exceptional situations
Permit fee formula: Flat fees. OSSF: Residential standard $325, residential multi-family $325, commercial/business $450, each additional RV at business sites $50, maintenance reports and contracts $5, affidavit aerobic or 10 acre exemption $25. Subdivision: major $750 initial and $750 approved, rural subdivision with road $750 initial and $750 approved, minor subdivision $500 initial and $500 approved, replat $250 plus posting/publishing initially and $250 on approval, recording of approved plat $250.

Fees change. Verify current amounts at the official fee schedule.

Work That Does NOT Require a Permit

Contact the Trinity County (County Judge's Office, Commissioners Court, Commissioners' Office, 911 Addressing and GIS Mapping) to confirm whether your project requires a permit before starting work.

Inspections

How to Schedule

Scheduling deadline: For OSSF, inspections must be requested before any lines or tanks are covered and should be requested at least two days prior to installation unless the assigned designated representative waives that lead time.

Typical inspection sequence: For OSSF: site evaluation, system design, permit application, county review, Authorization to Construct, installation, pre-cover inspection, and final approval. For aerobic systems, final permit release is held pending the recorded affidavit and maintenance documentation.

Additional Resources

Building code: No public countywide building-code adoption or general county building-code enforcement program was found.
Verify contractor license: TCEQ OSSF Permit Lookup and Authority Guidance
County Home Page
OSSF Main Page
County Forms with Commissioners and Heavy-Haul Links
911 Addressing and GIS
County Mitigation Plan
License lookup guide: Texas Contractor License Requirements
Contract template: Texas Homeowner-Contractor Agreement
Texas hub: Texas Contractor License & Permit Hub

Information on this page was last verified: March 2026. Permit rules and fees change — confirm current requirements directly with the Trinity County (County Judge's Office, Commissioners Court, Commissioners' Office, 911 Addressing and GIS Mapping) before applying.

Frequently Asked Questions

Trinity County Building Permit FAQ

Do I need a building permit in unincorporated Trinity County, TX?: No public countywide general building permit program was found for ordinary building construction in unincorporated Trinity County. Published county permit and approval controls include: OSSF and septic permits, subdivision and plat approval under county subdivision regulations, heavy-haul permits for county roads, and 911 address assignment and GIS coordination.
How much does a building permit cost in unincorporated Trinity County, TX?: The minimum permit fee is $5. Fees are calculated as: Flat fees. OSSF: Residential standard $325, residential multi-family $325, commercial/business $450, each additional RV at business sites $50, maintenance reports and contracts $5, affidavit aerobic or 10 acre exemption $25. Subdivision: major $750 initial and $750 approved, rural subdivision with road $750 initial and $750 approved, minor subdivision $500 initial and $500 approved, replat $250 plus posting/publishing initially and $250 on approval, recording of approved plat $250.. Plan check fee: Minor subdivision $3,000, rural subdivision with road $5,000, major subdivision $6,000, RV park $5,000, or amount set in consultation with engineer for exceptional situations.
How do I apply for a building permit in unincorporated Trinity County, TX?: 1. Determine whether the project falls into one of the county's published approval programs (OSSF, subdivision, heavy-haul, or addressing). 2. For OSSF and septic work, contact the County Judge's Office to obtain the permit application and packet. 3. Obtain a site evaluation from a licensed site evaluator and a septic design from a Texas licensed professional engineer or registered sanitarian, then submit those items with the permit application. 4. If the system uses secondary treatment (aerobic), provide the required affidavit to the public, maintenance agreement, and recorded documents before final operation approval. 5. Wait for county review. If compliant, the county issues an Authorization to Construct. 6. Request inspections before any lines or tanks are covered and at least two days before installation unless waived by the assigned designated representative. 7. For subdivision projects, follow county subdivision regulations and pay listed development and engineering-review fees. 8. For heavy-haul use on county roads, submit the permit through the Commissioners forms page before hauling begins.
What work is exempt from building permits in unincorporated Trinity County, TX?: The following work is generally exempt: OSSF work may qualify for state-law exemptions when statutory conditions are met, such as the Ten Acre Exemption affidavit. Note: No public county exempt-work list for general building work because no public countywide general building-permit program was found. For heavy-haul activity, the county publishes a Heavy Haul Permit form through the Commissioners forms page rather than an exemption list.

Need help with your project?

Navigating permits in Unincorporated Trinity County can be complicated.

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Important: This page is an educational resource provided by jaspector.com. It is not legal advice, and it does not substitute for official guidance from the permit authority listed above. Permit requirements, fees, and processes change frequently. Always verify current requirements directly with the issuing department before beginning any construction project. Use of this page does not create an attorney-client relationship. Jaspector assumes no liability for any outcomes arising from reliance on this information.

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