On this page 6
§ 02
When a permit is required
Permit triggers and exempt work for Knox County
A permit and approved plan are required to construct, alter, repair, extend, or operate an OSSF in unincorporated Knox County.
The 10 acre rule: a permit may be exempt if all stated conditions are met, including the required site evaluation, single-family residential use on a tract of 10 acres or more, and the stated setback and on-site disposal conditions
Emergency OSSF repairs are not required to obtain a permit, but the repairs must be reported to the permitting authority in writing within 72 hours after repairs begin
- Exempt The 10 acre rule: a permit may be exempt if all stated conditions are met, including the required site evaluation, single-family residential use on a tract of 10 acres or more, and the stated setback and on-site disposal conditions
- Exempt Emergency OSSF repairs are not required to obtain a permit, but the repairs must be reported to the permitting authority in writing within 72 hours after repairs begin
Note: For OSSF only. No public county exempt-work list for general building work was found.
Required documents
- Owner information
- Mailing address
- 911 site address
- Legal description support
- Water source information
- Site evaluator and installer information
- Planning materials as applicable
- Building code
- No public Knox County building code adoption or county building code enforcement page was found in the reviewed county materials.
- Permit validity
- Authorization to construct is valid for one calendar year from issuance. If the installer does not request a construction inspection within one year, the authorization expires and a new application and fee are required.
- Owner-builder
- A homeowner may install an OSSF if it is for a single-family dwelling the homeowner owns on property the homeowner owns, no part of the property is developed for sale or lease, and all permitting, construction, and maintenance requirements are met.
- Contractor requirements
- OSSF work must be performed by a licensed installer or directly by a qualifying homeowner under the homeowner exception.
Source: Knox County / Texas Commission on Environmental Quality Region 3 OSSF Program ↗
§ 03
Application process
Typical processing: TCEQ states OSSF permit applications must be approved or denied within 30 days of receipt
- 01 Verify the parcel is in unincorporated Knox County and not inside any incorporated city.
- 02 For septic work, use TCEQ OARS to confirm the permitting authority. Knox County returns REGION 03 - ABILENE as the authorized agent.
- 03 Arrange a site evaluation by a licensed site evaluator or professional engineer and gather the planning materials required for the proposed OSSF.
- 04 Complete TCEQ-0235 and assemble the required supporting materials, including owner information, site address, legal description support, water source data, site evaluation, and design or planning materials.
- 05 Submit the package and fee to TCEQ Region 3 in Abilene.
- 06 TCEQ must approve or deny the planning materials and permit application within 30 days of receipt.
- 07 Do not begin construction before authorization to construct is issued.
- 08 The installer must notify the permitting authority at least five working days before the system is ready for inspection.
- 09 The permitting authority conducts the construction inspection and issues deficiency notice if needed.
Typical processing time: TCEQ states OSSF permit applications must be approved or denied within 30 days of receipt
Source: Knox County / Texas Commission on Environmental Quality Region 3 OSSF Program ↗
§ 04
Fee schedule
Knox County building permit fees
Fee type
Amount
01
Permit fee formula
TCEQ states permit fees are paid to the authorized agent or the commission, whichever performs the permitting function.
Confirm the current OSSF fee amount and payment method directly with TCEQ Region 3 before submission because no Knox County-specific fee sheet was found.
§ 05
Required inspections
Scheduling and sequence
How to schedule
- TCEQ Region 3 (phone)
- Scheduling deadline
- The installer must notify the permitting authority at least five working days before the date the system will be ready for inspection.
- Inspection hours
- Monday through Friday, 8:00 a.m. to 5:00 p.m.
Typical sequence: OSSF authorization to construct, installation, notice to TCEQ Region 3, construction inspection, correction of deficiencies if needed, then approval before use.
Source: Knox County / Texas Commission on Environmental Quality Region 3 OSSF Program ↗
§ 06
Frequently asked
Common questions about unincorporated Knox County permits
01 Do I need a building permit in unincorporated Knox County, TX? ▸
A permit and approved plan are required to construct, alter, repair, extend, or operate an OSSF in unincorporated Knox County.
02 How much does a building permit cost in unincorporated Knox County, TX? ▸
Building permit fees in unincorporated Knox County, TX are set by the local building department and vary by project type and valuation. Fees are calculated as: TCEQ states permit fees are paid to the authorized agent or the commission, whichever performs the permitting function..
03 How do I apply for a building permit in unincorporated Knox County, TX? ▸
To apply for a building permit in unincorporated Knox County, TX, follow these steps: 1. Verify the parcel is in unincorporated Knox County and not inside any incorporated city. 2. For septic work, use TCEQ OARS to confirm the permitting authority. Knox County returns REGION 03 - ABILENE as the authorized agent. 3. Arrange a site evaluation by a licensed site evaluator or professional engineer and gather the planning materials required for the proposed OSSF. 4. Complete TCEQ-0235 and assemble the required supporting materials, including owner information, site address, legal description support, water source data, site evaluation, and design or planning materials. 5. Submit the package and fee to TCEQ Region 3 in Abilene. 6. TCEQ must approve or deny the planning materials and permit application within 30 days of receipt. 7. Do not begin construction before authorization to construct is issued. 8. The installer must notify the permitting authority at least five working days before the system is ready for inspection. 9. The permitting authority conducts the construction inspection and issues deficiency notice if needed.
04 How long does it take to get a building permit in unincorporated Knox County, TX? ▸
Building permit processing times in unincorporated Knox County, TX typically run TCEQ states OSSF permit applications must be approved or denied within 30 days of receipt. Timelines can vary based on project complexity and current department workload.
05 What work is exempt from building permits in unincorporated Knox County, TX? ▸
Not all construction work requires a permit in unincorporated Knox County, TX. The following work is generally exempt: The 10 acre rule: a permit may be exempt if all stated conditions are met, including the required site evaluation, single-family residential use on a tract of 10 acres or more, and the stated setback and on-site disposal conditions; Emergency OSSF repairs are not required to obtain a permit, but the repairs must be reported to the permitting authority in writing within 72 hours after repairs begin. Note: For OSSF only. No public county exempt-work list for general building work was found. When in doubt, confirm with the local building department before starting work.
06 How do I schedule a building inspection in unincorporated Knox County, TX? ▸
Once your permit is issued and work reaches an inspection milestone, you can schedule a building inspection in unincorporated Knox County, TX via: TCEQ Region 3. The installer must notify the permitting authority at least five working days before the date the system will be ready for inspection..
last verified April 2026
source Knox County / Texas Commission on Environmental Quality Region 3 OSSF Program ↗
entry id permits/texas/knox/unincorporated
Educational reference. Permit rules and fees change — confirm current requirements directly with Knox County / Texas Commission on Environmental Quality Region 3 OSSF Program before applying. Jaspector is not legal advice.