Knox County, TX Building Permits, Zoning & Septic Rules

Unincorporated Knox County, Texas does not require a building permit for a home, and the county has no zoning ordinance, so there is no minimum home size, setback rule, or restriction on RVs, tiny homes, or manufactured homes¹²³. A septic system still needs a state OSSF permit, and because Knox County has no local authorized agent, that permit comes from TCEQ's Region 3 office in Abilene⁴⁵. Water wells are different: most wells here need a permit from the Rolling Plains Groundwater Conservation District before drilling, unless a small-well exemption applies⁶.

At a glance

Building permit: Not required in unincorporated Knox County¹
Zoning: No county zoning; Knox County cannot zone under Texas law²
Septic permit: Required through TCEQ's regional office in Abilene; a 10-acre exemption may apply⁴⁷
Water well permit: Required from the Rolling Plains Groundwater Conservation District above small-well exemption thresholds⁶
RV / tiny home / manufactured home: Unrestricted by county zoning (there is none)³
Minimum home size / setbacks: None set by the county (no zoning ordinance)³
Septic soils: Only about 11.6% of the county's soils are rated without severe limits for a conventional drain field⁸
Owner-builder exemption: Not published anywhere we could find; unconfirmed⁹

Who to call

Septic permits

TCEQ Region 3 (Abilene) Office

OSSF (septic) permitting authority for Knox County. TCEQ's own county lookup tool returns this office, not a city or county authorized agent, as Knox County's permitting authority, matching Knox County's own website, which names no Sanitarian, health, or septic office of its own.

325-698-9674

1977 Industrial Blvd, Abilene, TX 79602-7833

Online permits →

Well permits

Rolling Plains Groundwater Conservation District

Permits and registers water wells in its territory, which includes Knox County. Its own rules require a District permit before drilling or increasing production above 25,000 gallons per day, with narrower exemptions for small domestic and livestock wells.

(940) 422-1095

[email protected]

110 W California Street, Seymour, TX 76380

Also useful

Knox County Judge / Commissioners Court

Presides over Commissioners Court, the county's governing body; general point of contact for county roads and anything not covered by a named county office. Knox County's own office list names no building, zoning, or planning department.

940-459-2191

P.O. Box 77, Benjamin, Texas 79505

Contact details are copied from each office’s official page and were checked against it on September 24, 2026.

Do you need a building permit in Knox County, Texas?

No: unincorporated Knox County has no building or codes department, and its own website lists only elected offices like the County Judge, Commissioners Court, and Sheriff¹. Texas abolished statewide mandatory residential building-code enforcement, and general-law counties like Knox County have only narrow, specific permitting powers granted by the legislature, none of which cover ordinary site-built homes here¹¹⁰. Texas does let some counties adopt a fire code or a residential-code resolution, but that authority is limited to counties over 250,000 people (or adjacent to one) for the fire code, and to counties within 50 miles of the international border or with a specific population threshold for the residential-code option; Knox County's population of about 3,302 does not put it in either category¹⁰¹¹.

Who handles permits, septic, and wells in Knox County, and how do you reach them?

Knox County has no building or zoning department, and its own office list names only the County Judge, Commissioners Court, County Attorney, County Clerk, County Treasurer, Tax Assessor/Collector, and Sheriff¹². For a septic permit, contact TCEQ's Region 3 office directly at 1977 Industrial Blvd, Abilene, TX 79602-7833, phone 325-698-9674⁵. For a water well permit, contact the Rolling Plains Groundwater Conservation District at 110 W California Street, Seymour, TX 76380, phone (940) 422-1095¹². For anything else county government handles, including roads, the County Judge's office at P.O. Box 77, Benjamin, Texas 79505, phone 940-459-2191, is the place to start¹³.

Does Knox County have zoning?

Knox County has no zoning ordinance and, as a general-law county, cannot adopt one for unincorporated land². Texas gives counties zoning power only for a short list of specific places named in state law, like parts of Padre Island, the Amistad Recreation Area, and a few named lakes, and Knox County is not one of them¹⁴. Because there is no county zoning ordinance, there is no minimum lot size, setback rule, height limit, or dwelling-size minimum, and RVs, tiny homes, manufactured homes, and accessory dwellings are unrestricted by county zoning³.

How do septic and water well permits work in Knox County?

Any on-site sewage facility (OSSF) in Knox County needs a state permit before you build it⁴⁷. Because Knox County has no local authorized agent, TCEQ's Region 3 office in Abilene is the permitting authority, confirmed by TCEQ's own county-lookup tool, which returns "Region 03 - Abilene" as Knox County's sole authorized agent⁵. If your tract is at least 10 acres, you may qualify for an exemption from the permit, inspection, and planning-materials requirements, but every condition has to be met: no nuisance or groundwater pollution, every part of the system at least 100 feet from the property line, effluent disposed of entirely on your own property, and the single-family home as the only dwelling on the tract¹⁵. Soils here are tough for a conventional system: only about 11.6% of Knox County's land is rated without severe limits for a drain field, so get a site evaluation before you count on the cheapest option⁸. For water wells, most of Knox County sits in the Rolling Plains Groundwater Conservation District, which requires a District permit before drilling or increasing production above 25,000 gallons per day; domestic or livestock wells on tracts over 10 acres pumping less are exempt from the permit but must still register, and a small pump of one-half horsepower or less on a tract under 10 acres is exempt outright⁶.

Can you live in an RV or tiny home on your land in Knox County?

Unincorporated Knox County has no zoning ordinance, so there is no county rule against living in an RV, tiny home, or manufactured home on your own land³. That does not remove the septic requirement: whatever you live in, if it is not on a public sewer you still need a permitted OSSF, or you need to qualify for the 10-acre exemption, before you can legally use a toilet there⁷. A factory-built structure sold as "industrialized housing" (as opposed to an ordinary manufactured or mobile home) has to meet Texas's mandatory 2021-edition building codes regardless of county zoning¹⁶.

Building a home in Knox County: the steps, in order

Confirm your OSSF plan with TCEQ Region 3 (1977 Industrial Blvd, Abilene, TX 79602-7833; 325-698-9674), or check whether your tract qualifies for the 10-acre exemption instead⁵¹⁵.
If you're drilling a well, contact the Rolling Plains Groundwater Conservation District (110 W California Street, Seymour, TX 76380; (940) 422-1095) to check whether your planned well needs a District permit or qualifies for a small-well exemption¹²⁶.
If you don't qualify for the septic exemption, get a site evaluation; Knox County's soils are rated without severe limits on only about 11.6% of the land, so this step matters⁸.
Submit your OSSF application to TCEQ Region 3 and, separately, apply for a well permit if the District requires one for your planned well⁵¹².
If your driveway will connect to a state highway, apply for a TxDOT access driveway permit on Form 1058 before you build it¹⁷.
Build: unincorporated Knox County has no county building permit or inspection requirement, so no county sign-off is needed to start construction on an ordinary site-built home¹.
If anything else comes up that isn't covered by a named county office, call the County Judge's office at 940-459-2191¹³.

What to check before you buy land in Knox County

Septic: get a site evaluation before you buy, since only about 11.6% of the county's soils are rated without severe limits for a conventional drain field, and find out whether your tract is large enough (10 acres or more) to qualify for the state's septic-permit exemption⁸¹⁵. Water: check with the Rolling Plains Groundwater Conservation District about whether your planned well needs a District permit, since most wells above the small-well exemptions do⁶. Access: a driveway onto a state highway needs a TxDOT permit on Form 1058, paid for and built to TxDOT's standards¹⁷. Zoning: there is none in unincorporated Knox County, and none is coming, since the county has no legal authority to adopt it²¹⁴. Climate: this is dry, hot country, with about 25.3 inches of rain a year and severe drought in nearly 39.3% of years historically¹⁸¹⁹. Taxes: Knox County's effective property tax rate runs about 1.9%, with a median annual property tax bill around $1,244²⁰²¹. The county is very sparsely populated, at about 3.9 people per square mile, with the nearest metro area roughly 73 miles away²²²³.

Watch-outs

Factory-built "industrialized housing," as distinct from an ordinary manufactured or mobile home, must meet Texas's mandatory building, energy, and electrical codes (2021-edition IBC/IRC with amendments) for construction starting on or after July 1, 2024, even though Knox County itself has no building-permit requirement¹⁶.
We could not confirm whether Knox County has any local rule on driveway access to county or local roads (as opposed to state highways, which do need a TxDOT permit); ask the County Judge's office before you build a new approach¹³.
We could not confirm building-inspection requirements, certificate-of-occupancy rules, or a short-term-rental ordinance for Knox County; the county's own website does not publish any of these, so ask the County Judge's office directly rather than assume none exist¹³¹.

Sources

Written September 24, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.

How Knox County scores

Seclusion87100% ev.

Self-Sufficiency2396% ev.

Admin Boringness8290% ev.

Durability29100% ev.

Property Autonomy71100% ev.

Carry Cost80100% ev.

Evidence strength: 97%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$83kTypical home

1.9%Property tax

$1,983Land / acre

25.3"Annual rain

39.3% of yrsSevere drought

62.9 / yr (+33)Mid-century 100°F days

29.9 daysMid-century dry spell

1.75" (+6%)Mid-century 1-day rain

1.31×Wildfire change factor

100%Forward climate coverage

$2,555Home insurance / yr

-3% / yrInsurance growth

0%Nonrenewal rate

county median (2+ published ZIPs)Insurance basis

206,643People within 2 hr

2,097Radius comparison (15 mi)

3.9People / sq mi

0.5%Federal land

100%Land at 15% slope or less

11.6%Septic soil without severe limits

62,134 acWorkable land screen

11.1%Wooded land

4.8 tonsBiomass / forest ac

64.2°FAvg temp

Answers from the rulebook for Knox County

What the ordinances and state agencies actually say — one answer per question, each quoted from the official source and independently re-checked.

Knox County rules

Zoning districts · by state lawNo county rule
Unincorporated Knox County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Knox County has no zoning ordinance. The county legal census found no county zoning ordinance, citing knoxcountytexas.org.
- Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
- Chapter 231 does not grant a general statewide county zoning power; authority is provided through geographically or subject-matter limited subchapters.
- For Padre Island, the authority applies in Cameron or Willacy County outside a municipality and within two miles of a publicly owned park or recreational development, or within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.
“This subchapter applies to the areas of Padre Island located in Cameron or Willacy County and located: (1) outside a municipality but within two miles of a publicly owned park or recreational development; or (2) within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.”
Local Government Code Chapter 231, County Zoning Authority ↗Re-checked Sep 21, 2026
Minimum dwelling size · by state lawNo county rule
Unincorporated Knox County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Knox County has no zoning ordinance. The county legal census found no county zoning ordinance, citing knoxcountytexas.org.
- Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
- Chapter 231 does not grant a general statewide county zoning power; authority is provided through geographically or subject-matter limited subchapters.
- For Padre Island, the authority applies in Cameron or Willacy County outside a municipality and within two miles of a publicly owned park or recreational development, or within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.
“This subchapter applies to the areas of Padre Island located in Cameron or Willacy County and located: (1) outside a municipality but within two miles of a publicly owned park or recreational development; or (2) within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.”
Local Government Code Chapter 231, County Zoning Authority ↗Re-checked Sep 21, 2026
Minimum lot size · by state lawNo county rule
Unincorporated Knox County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Knox County has no zoning ordinance. The county legal census found no county zoning ordinance, citing knoxcountytexas.org.
- Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
- Chapter 231 does not grant a general statewide county zoning power; authority is provided through geographically or subject-matter limited subchapters.
- For Padre Island, the authority applies in Cameron or Willacy County outside a municipality and within two miles of a publicly owned park or recreational development, or within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.
“This subchapter applies to the areas of Padre Island located in Cameron or Willacy County and located: (1) outside a municipality but within two miles of a publicly owned park or recreational development; or (2) within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.”
Local Government Code Chapter 231, County Zoning Authority ↗Re-checked Sep 21, 2026
Setbacks · by state lawNo county rule
Unincorporated Knox County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Knox County has no zoning ordinance. The county legal census found no county zoning ordinance, citing knoxcountytexas.org.
- Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
- Chapter 231 does not grant a general statewide county zoning power; authority is provided through geographically or subject-matter limited subchapters.
- For Padre Island, the authority applies in Cameron or Willacy County outside a municipality and within two miles of a publicly owned park or recreational development, or within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.
“This subchapter applies to the areas of Padre Island located in Cameron or Willacy County and located: (1) outside a municipality but within two miles of a publicly owned park or recreational development; or (2) within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.”
Local Government Code Chapter 231, County Zoning Authority ↗Re-checked Sep 21, 2026
Lot coverage · by state lawNo county rule
Unincorporated Knox County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Knox County has no zoning ordinance. The county legal census found no county zoning ordinance, citing knoxcountytexas.org.
- Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
- Chapter 231 does not grant a general statewide county zoning power; authority is provided through geographically or subject-matter limited subchapters.
- For Padre Island, the authority applies in Cameron or Willacy County outside a municipality and within two miles of a publicly owned park or recreational development, or within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.
“This subchapter applies to the areas of Padre Island located in Cameron or Willacy County and located: (1) outside a municipality but within two miles of a publicly owned park or recreational development; or (2) within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.”
Local Government Code Chapter 231, County Zoning Authority ↗Re-checked Sep 21, 2026
Building height · by state lawNo county rule
Unincorporated Knox County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Knox County has no zoning ordinance. The county legal census found no county zoning ordinance, citing knoxcountytexas.org.
- Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
- Chapter 231 does not grant a general statewide county zoning power; authority is provided through geographically or subject-matter limited subchapters.
- For Padre Island, the authority applies in Cameron or Willacy County outside a municipality and within two miles of a publicly owned park or recreational development, or within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.
“This subchapter applies to the areas of Padre Island located in Cameron or Willacy County and located: (1) outside a municipality but within two miles of a publicly owned park or recreational development; or (2) within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.”
Local Government Code Chapter 231, County Zoning Authority ↗Re-checked Sep 21, 2026
Living in an RV · by state lawNo county rule
Unincorporated Knox County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Knox County has no zoning ordinance. The county legal census found no county zoning ordinance, citing knoxcountytexas.org.
- Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
- Chapter 231 does not grant a general statewide county zoning power; authority is provided through geographically or subject-matter limited subchapters.
- For Padre Island, the authority applies in Cameron or Willacy County outside a municipality and within two miles of a publicly owned park or recreational development, or within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.
“This subchapter applies to the areas of Padre Island located in Cameron or Willacy County and located: (1) outside a municipality but within two miles of a publicly owned park or recreational development; or (2) within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.”
Local Government Code Chapter 231, County Zoning Authority ↗Re-checked Sep 21, 2026
Camping on your land · by state lawNo county rule
Unincorporated Knox County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Knox County has no zoning ordinance. The county legal census found no county zoning ordinance, citing knoxcountytexas.org.
- Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
- Chapter 231 does not grant a general statewide county zoning power; authority is provided through geographically or subject-matter limited subchapters.
- For Padre Island, the authority applies in Cameron or Willacy County outside a municipality and within two miles of a publicly owned park or recreational development, or within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.
“This subchapter applies to the areas of Padre Island located in Cameron or Willacy County and located: (1) outside a municipality but within two miles of a publicly owned park or recreational development; or (2) within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.”
Local Government Code Chapter 231, County Zoning Authority ↗Re-checked Sep 21, 2026
Tiny homes · by state lawNo county rule
Unincorporated Knox County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Knox County has no zoning ordinance. The county legal census found no county zoning ordinance, citing knoxcountytexas.org.
- Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
- Chapter 231 does not grant a general statewide county zoning power; authority is provided through geographically or subject-matter limited subchapters.
- For Padre Island, the authority applies in Cameron or Willacy County outside a municipality and within two miles of a publicly owned park or recreational development, or within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.
“This subchapter applies to the areas of Padre Island located in Cameron or Willacy County and located: (1) outside a municipality but within two miles of a publicly owned park or recreational development; or (2) within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.”
Local Government Code Chapter 231, County Zoning Authority ↗Re-checked Sep 21, 2026
Manufactured homes · by state lawNo county rule
Unincorporated Knox County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Knox County has no zoning ordinance. The county legal census found no county zoning ordinance, citing knoxcountytexas.org.
- Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
- Chapter 231 does not grant a general statewide county zoning power; authority is provided through geographically or subject-matter limited subchapters.
- For Padre Island, the authority applies in Cameron or Willacy County outside a municipality and within two miles of a publicly owned park or recreational development, or within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.
“This subchapter applies to the areas of Padre Island located in Cameron or Willacy County and located: (1) outside a municipality but within two miles of a publicly owned park or recreational development; or (2) within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.”
Local Government Code Chapter 231, County Zoning Authority ↗Re-checked Sep 21, 2026
Accessory dwellings · by state lawNo county rule
Unincorporated Knox County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Knox County has no zoning ordinance. The county legal census found no county zoning ordinance, citing knoxcountytexas.org.
- Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
- Chapter 231 does not grant a general statewide county zoning power; authority is provided through geographically or subject-matter limited subchapters.
- For Padre Island, the authority applies in Cameron or Willacy County outside a municipality and within two miles of a publicly owned park or recreational development, or within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.
“This subchapter applies to the areas of Padre Island located in Cameron or Willacy County and located: (1) outside a municipality but within two miles of a publicly owned park or recreational development; or (2) within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.”
Local Government Code Chapter 231, County Zoning Authority ↗Re-checked Sep 21, 2026
Well permitLimited
Water wells in the Rolling Plains Groundwater Conservation District portion of Knox County, including domestic, livestock, irrigation, and other wells.
- Except for wells exempt under Rule 8.5, a District permit is required before drilling or increasing production or pumping capability above 25,000 gallons per day.
- Exempt wells must generally be registered with the District before drilling.
- Domestic or livestock wells producing less than 25,000 gallons per day on parcels greater than 10 acres are exempt from permitting but require registration.
- Domestic or livestock wells with a pump of one-half horsepower or less on parcels less than 10 acres are exempt from permitting.
- Petroleum-rig wells meeting the stated Railroad Commission conditions are exempt from permitting but must be registered and metered.
- A well permit application is subject to District rules, required information, and District review.
permit threshold: > 25000 gallons per day (Certain Rule 8.5 exemptions apply.) · equivalent permit threshold: 17.36 gallons per minute (District rule states this is equivalent to 25,000 gallons per day.) · domestic/livestock exemption parcel size: > 10 acres (Well must produce less than 25,000 gallons per day.) · small-pump exemption: <= 0.5 horsepower (Domestic or livestock use on parcels less than 10 acres.)
“Except for those wells exempt under Rule 8.5, a person is required to obtain a permit from the District.”
Groundwater Conservation District Information ↗Re-checked Sep 11, 2026
Building permitNot required
Rural Knox County (seat Benjamin, TX) shows no county building-permit program; Texas counties generally lack authority to require residential building permits in unincorporated areas.
Knox County, Texas official website ↗Scouted from the county site, not yet independently re-checked
County-wide zoningAbsent
No county zoning ordinance is evident; Texas counties generally cannot zone unincorporated land.
Knox County, Texas official website ↗Scouted from the county site, not yet independently re-checked

Texas rules that apply here

Building code adoptedPartial
Industrialized housing and buildings, modules, and modular components governed by the Texas Industrialized Housing and Buildings program.
- The mandatory state code adoption applies to industrialized housing and buildings, modules, and modular components, not all construction statewide.
- The effective date is July 1, 2024.
- The International Existing Building Code applies to alterations of portable industrialized buildings.
- Manufacturers already certified for Texas must have design-package documents reviewed and approved to the new editions with an approval date on or after July 1, 2024, unless the manufacturer elected to transition before the effective date under Department rule 70.70(a)(5)(B).
- Construction begun on or after July 1, 2024 must comply with the new code editions and approved design packages.
- Construction begun before July 1, 2024, or before a manufacturer's effective transition date, must meet the stated completion, inspection, and labeling deadline to remain eligible for a Texas decal.
effective date: 2024-07-01 · International Building Code: 2021 Edition (including appendices C, F, and K) · International Residential Code: 2021 Edition (including appendices AG, AH, AK, AP, AQ, and AT) · International Fuel Gas Code: 2021 Edition · International Mechanical Code: 2021 Edition · International Plumbing Code: 2021 Edition · International Energy Conservation Code: 2015 Edition · National Electrical Code: 2020 Edition · International Existing Building Code: 2021 Edition (for alterations of portable industrialized buildings)
“July 1, 2024, all industrialized housing and buildings, modules, and modular components shall comply with the following codes, as amended in §70.101 of the IHB Rules:”
Industrialized Housing and Buildings – Adoption of New Code Editions ↗Re-checked Sep 12, 2026
Who permits septicMixed
On-site sewage facilities, including septic systems, throughout Texas
- In most areas, local governments act as TCEQ-authorized agents and administer the OSSF program.
- The TCEQ regional office is the permitting authority where a local jurisdiction has not been authorized.
- Local permitting programs may be more stringent than state minimums.
“TCEQ is not often the OSSF permitting authority. [...] The TCEQ regional office will be the permitting authority in locations where a local jurisdiction has not been authorized.”
Getting a Permit for an OSSF - Such as a Septic System ↗Re-checked Sep 12, 2026
Septic permitRequired
Construction, installation, alteration, extension, or repair of an OSSF in Texas
- A permit and approved plan are required to construct, alter, repair, extend, and operate an OSSF.
- A 10-acre exemption may apply only if all listed conditions are met: site evaluation by a TCEQ-licensed site evaluator or professional engineer; single-family dwelling on at least 10 acres; no nuisance or groundwater pollution; all OSSF parts at least 100 feet from the property line; effluent disposed of on the property; and the single-family dwelling is the only dwelling on the tract.
- Emergency repairs listed by TCEQ do not require a permit but must be reported in writing to the permitting authority within 72 hours after repairs begin.
- Grandfathered systems may also be exempt if the stated conditions are met.
minimum tract size for 10-acre exemption: >= 10 acres (single-family dwelling and all other TCEQ conditions must be met) · minimum OSSF distance from property line for 10-acre exemption: >= 100 feet (all parts of the OSSF) · emergency repair reporting deadline: <= 72 hours (after repairs have begun; written report to permitting authority)
“A permit is required to construct, install, alter, extend, or repair an OSSF. [...] An OSSF may be exempt from permitting if it complies with all other requirements, including planning, construction, and installation standards of 30 TAC 285 AND meets the “10 acre rule”:”
Getting a Permit for an OSSF - Such as a Septic System ↗Re-checked Sep 12, 2026
Septic inspectionLimited
Construction inspection of permitted on-site sewage facilities in Knox County, Texas.
- The installer must notify the permitting authority at least five working days before the OSSF is ready for inspection.
- The permitting authority shall conduct a construction inspection.
- If the OSSF fails inspection, it cannot be used until it passes inspection.
- A reinspection fee may be assessed and must be paid before reinspection.
- The 10-acre single-family-dwelling exception eliminates inspection only when all listed exception conditions are met.
inspection notice period: 5 working days (Monday through Friday, excluding holidays.) · reinspection fee: may be assessed (Must be paid before reinspection.)
“The installer shall notify the permitting authority at least five working days (Monday through Friday, excluding holidays) before the date the OSSF will be ready for inspection. (3) The permitting authority shall conduct a construction inspection.”
On-Site Sewage Facility Rules Compilation ↗Re-checked Sep 11, 2026
One more reviewed finding on this topic
- Limited — OSSF installation and, where applicable, maintenance inspections in Texas
  “Many times, the AA has a "designated representative" (DR) to assist them with their responsibilities, which include reviewing plans for constructing, altering, extending or repairing each OSSF; issuing permits; and inspecting system installation. [...] If the system uses an electronic monitor, automatic radio or telephone to notify the maintenance provider of system or component failure and to monitor the amount of disinfection in the system, reporting may be reduced to every six months.”
  Basics for Septic Systems ↗Re-checked Sep 12, 2026
Off-grid sanitationLimited
On-site sanitation using an OSSF for a single-family dwelling in Knox County, Texas.
- A single-family dwelling on a tract of at least 10 acres may use an OSSF without planning materials, a permit, or an inspection only if the OSSF is not causing a nuisance or polluting groundwater, all OSSF parts are at least 100 feet from the property line, effluent is disposed of on the property, and the dwelling is the only dwelling on the tract.
- Other OSSF construction, alteration, repair, extension, or operation generally requires a permit and approved plan.
minimum tract size: >= 10 acres (Single-family dwelling and all other listed conditions required.) · minimum setback of all OSSF parts from property line: >= 100 feet (Single-family dwelling and all other listed conditions required.)
“No planning materials, permit, or inspection are required for an OSSF for a single family dwelling located on a tract of land that is ten acres or larger and: (A) the OSSF is not causing a nuisance or polluting groundwater; (B) all parts of the OSSF are at least 100 feet from the property line; (C) the effluent is disposed of on the property; and (D) the single family dwelling is the only dwelling located on that tract of land.”
On-Site Sewage Facility Rules Compilation ↗Re-checked Sep 11, 2026
Driveway accessRequired
New or modified access driveways connecting property to a Texas state highway right of way.
- A local public agency may receive access driveway permitting authority for state highways, but TxDOT approval remains required for drainage impacts on the state highway system before local approval.
- No access driveway is permitted within a flared or widened right-of-way section at an intersection of a state highway with another highway, road, or street.
- All entrances and exits, including radii, must be confined within the permittee's property frontage.
- One-way 45-to-90-degree driveways are permitted for connections to one-way frontage roads or lane-divided highways; otherwise the driveway angle must be 75 to 90 degrees.
- ADAAG and Texas Accessibility Standards apply.
private residential driveway maximum width: <= 24 feet (Except as increased by permissible radii.) · driveway-to-pavement radius: >= 15 feet
“A driveway must be constructed in accordance with a fully executed driveway permit”
Section 4: Driveway Permits, Design, and Materials ↗Re-checked Sep 12, 2026
Permit feesPublished (with conditions)
OSSF permit fees in areas where the TCEQ executive director, rather than a local authorized agent, administers the program; this is the state rule relevant when no local authorized agent exists.
- The fee schedule is in Subchapter C for areas where no authorized agent exists.
- The application fee is $200 for an OSSF serving a single-family dwelling or $400 for all other types of OSSFs.
- A $10 fee is collected for each OSSF permit for the commission under Texas Health and Safety Code Chapter 367.
- Fees are payable when the owner or owner's agent applies; payment is submitted to the appropriate regional office by money order or check payable to the Texas Commission on Environmental Quality.
- The re-inspection fee equals one-half of the permit fee in effect when the original application was submitted to the regional office.
- Application fees are nonrefundable.
- The cited rule states adopted July 25, 2012 and effective August 16, 2012; the publication is revised May 2017.
single-family OSSF application fee: 200 USD · other OSSF application fee: 400 USD · commission fee per OSSF permit: 10 USD (Collected under Texas Health and Safety Code, Chapter 367.) · re-inspection fee: one-half of the permit fee in effect at original application text
“The application fee for an on-site sewage facility (OSSF) permit is: (1) $200 for an OSSF serving a single family dwelling; or (2) $400”
On-Site Sewage Facility Rules Compilation ↗Re-checked Sep 11, 2026
Permit processPublished (with conditions)
Constructing a new driveway or revising an existing driveway on the right of way of a Texas state highway.
- The applicant should contact the local District TxDOT office.
- The applicant must submit Form 1058, Permit to Construct Access Driveway Facilities on Highway Right of Way.
- The application must be for the bona fide purpose of securing or changing access to the owner's property, not parking or servicing vehicles on state highway rights of way.
- No construction may begin on the right of way until a fully executed driveway permit is received and the applicant gives TxDOT 24-hour notification.
- The driveway must comply with the executed permit and applicable regulations; TxDOT inspection must find construction satisfactory.
- Where a local public agency has permitting authority, drainage impacts on the state highway system still require TxDOT approval before local approval.
- Driveway geometrics, utilities, environmental requirements, wetlands considerations, ADAAG, TAS, and other applicable state and federal laws must be considered.
required form: Form 1058, Permit to Construct Access Driveway Facilities on Highway Right of Way · advance notification: 24 hours (Notification to TxDOT is required before construction on the right of way.) · private residential driveway maximum width: <= 24 feet (Except as increased by permissible radii.) · minimum driveway radius to highway pavement: >= 15 feet
“The applicant shall complete and submit to TxDOT a Form 1058”
Section 4: Driveway Permits, Design, and Materials ↗Re-checked Sep 12, 2026
county zoning authorityLimited
Texas counties adopting zoning regulations for specified unincorporated or otherwise specially defined areas.
- Chapter 231 does not grant a general statewide county zoning power; authority is provided through geographically or subject-matter limited subchapters.
- For Padre Island, the authority applies in Cameron or Willacy County outside a municipality and within two miles of a publicly owned park or recreational development, or within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.
- Other Chapter 231 subchapters address special areas including the Amistad Recreation Area in Val Verde County, military zones, certain lakes, the El Paso Mission Trail Historical Area, Lake Somerville, and Falcon Lake in Zapata County.
- The cited statute was enacted effective September 1, 1987; the Falcon Lake subchapter was added effective June 15, 2007, and amended effective September 1, 2009.
Padre Island distance from publicly owned park or recreational development: <= 2 miles (Area must be outside a municipality and in Cameron or Willacy County.) · Padre Island distance from beach, wharf, or bathhouse: <= 2 miles (The beach, wharf, or bathhouse must be used by at least 500 persons annually.)
“This subchapter applies to the areas of Padre Island located in Cameron or Willacy County and located: (1) outside a municipality but within two miles of a publicly owned park or recreational development; or (2) within two miles of a beach, wharf, or bathhouse used by at least 500 persons annually.”
Local Government Code Chapter 231, County Zoning Authority ↗Re-checked Sep 21, 2026
county building authorityLimited
Texas counties adopting and enforcing fire-code building permits for specified buildings in unincorporated areas and applying residential building-code standards in certain counties.
- Under Section 233.061, the county must have a population over 250,000 or be adjacent to a county with a population over 250,000.
- Under Section 233.062, the fire code applies only to commercial establishments, public buildings, and multifamily residential dwellings consisting of four or more units constructed in an unincorporated area.
- The fire code does not apply to an industrial facility having a fire brigade that conforms to Occupational Health and Safety Administration requirements.
- A covered applicant must submit a plan and a commissioners-court-set application fee; the county must issue or deny the permit within 30 days, and failure to act within 30 days approves the construction for purposes of the subchapter.
- The fire code must conform to the International Fire Code or Uniform Fire Code as those codes existed on May 1, 2005, or establish protective measures exceeding those standards; later editions may be adopted.
- Residential standards under Section 233.152 apply only if the county adopts a resolution or order and the county is within 50 miles of an international border or has a population over 100.
- Those residential standards apply only to new single-family-house or duplex construction beginning after September 1, 2009; manufactured or modular structures governed by Occupations Code Chapters 1201 or 1202 are excluded from the definition of new residential construction.
- A municipality's building code controls in its extraterritorial jurisdiction, and Section 233.152 does not authorize county prior approval of new residential construction or county zoning regulations.
- Fire-code inspection and permit fees may be charged under a fee schedule based on building type, limited to amounts necessary to administer and enforce the subchapter; inspection fees must be reasonable and reflect approximate inspection costs.
county population threshold for fire-code authority: > 250000 persons (A county adjacent to a county over 250,000 also qualifies.) · multifamily residential dwelling threshold: >= 4 units (The fire code applies only to covered buildings constructed in an unincorporated area.) · residential-code border distance: <= 50 miles (Alternative qualification is county population over 100.) · application decision period: 30 days (If the commissioners court does not issue or deny the permit within 30 days after receiving the application and fee, construction is approved for purposes of the subchapter.) · residential standards effective construction date: > 2009-09-01 (Applies only to new residential construction that begins after September 1, 2009.)
“The commissioners court of a county with a population of over 250,000 or a county adjacent to a county with a population of over 250,000 may adopt a fire code and rules necessary to administer and enforce the fire code. [...] The fire code applies only to the following buildings constructed in an unincorporated area of the county: (1) a commercial establishment; (2) a public building; and (3) a multifamily residential dwelling consisting of four or more units.”
Local Government Code Chapter 233, County Regulation of Housing and Other Structures ↗Re-checked Sep 21, 2026

Still unanswered

We looked and could not find an official answer yet. Silence is not permission — ask the county directly.

Owner-builder exemption — Owner-builder exemptions from building-permit, inspection, or occupancy requirements in Knox County.
Inspections — Building inspections for construction in Knox County.
Certificate of occupancy — Certificates of occupancy for buildings in Knox County.
Local zoning — Aggregate local zoning controls within Knox County, including incorporated municipalities and unincorporated areas.
Mandatory utility hookup — Required connection to public water or wastewater utilities for property in Knox County, Texas.

2 more unanswered

Building in a floodplain
Short-term rentals

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Living off-grid in Knox County, Texas

Is Knox County a good place to live off-grid or homestead?

Knox County scores 51/100 on the Bolthole Index, a solid county profile. Its strengths: deep seclusion — about 2,097 people within 15 miles and low administrative friction for a quiet rural property. Watch-outs: workable self-sufficiency basics (25.3″/yr rainfall) and elevated mid-century heat, water, rain, or wildfire exposure.

Do you need a building permit in Knox County, Texas?

Knox County does not require a county building permit for a home in unincorporated areas, and it has no county-wide zoning. Onsite septic is permitted by Texas Commission on Environmental Quality (TCEQ) regional office (permitting authority where no local authorized agent exists). These answers are quoted from official sources and independently re-checked. Rules change and cities within the county differ — always confirm with the county before you buy or build.

Can you live in an RV or tiny home on your land in Knox County?

Living in an RV on your own land in Knox County is allowed: Unincorporated Knox County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Knox County has no zoning ordinance. The county legal census found no county zoning ordinance, citing knoxcountytexas.org. Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits. Chapter 231 does not grant a general statewide county zoning power; authority is provided through geographically or subject-matter limited subchapters. A tiny home is allowed. Confirm with the county before relying on it.

How much does land cost in Knox County, Texas?

Land in Knox County runs about $1,983 per acre, based on the latest county data.

What is the water situation in Knox County?

Knox County gets about 25.3" of rain a year, with severe drought in roughly 39.3% of years.

How remote is Knox County?

A typical private-land location has about 2,097 people within 15 miles and 506,619 within 100 miles. These radius catchments are the published fallback where road routing is unavailable.

Building permits, zoning and land rules in Knox County, Texas

At a glance

Who to call

Do you need a building permit in Knox County, Texas?

Who handles permits, septic, and wells in Knox County, and how do you reach them?

Does Knox County have zoning?

How do septic and water well permits work in Knox County?

Can you live in an RV or tiny home on your land in Knox County?

Building a home in Knox County: the steps, in order

What to check before you buy land in Knox County

Watch-outs

Sources

Knox County in Texas

How Knox County scores

Find land. Bring the promising ones back.

Parcel due diligence

Answers from the rulebook for Knox County

Knox County rules

Texas rules that apply here

Still unanswered

Living off-grid in Knox County, Texas

Is Knox County a good place to live off-grid or homestead?

Do you need a building permit in Knox County, Texas?

Can you live in an RV or tiny home on your land in Knox County?

How much does land cost in Knox County, Texas?

What is the water situation in Knox County?

How remote is Knox County?

How Knox compares in Texas