Bolthole Index

Mills County, Texas

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

70Index Score / 100
#38 of 254 in Texas

Unincorporated Mills County, Texas has no building permit and no zoning ordinance: Texas gives most counties no authority to require prior approval for home construction, and zoning power is reserved for specific counties that Mills isn't one of12. That means no county rule sets minimum lot size, setbacks or where you can put an RV or tiny home3. What Mills County does require is an on-site sewage facility (OSSF) permit for septic, a driveway permit if you'll access a county road, and a floodplain development permit in mapped flood hazard areas, all through the County Judge's office4.

At a glance

Building permit
Not required in unincorporated Mills County1
County zoning
None; Texas reserves zoning power to specific counties and Mills isn't one25
Septic (OSSF) permit
Required through the County Judge's office; $335 application/inspection fee as of 9/1/20256
RV, tiny home & manufactured home
Unrestricted by county rule; the county has no zoning authority to limit them3
Setbacks & minimum lot size
None set by the county3
Owner-builder
You can build your own home and, if you have the skills, install your own OSSF on your own single-family property7
County-road driveway access
$50 permit from the County Judge's office required before work starts8

Who to call

Also useful

Mills County Judge's Office

General county administration; the intake point for OSSF (septic) permit applications, county-road driveway/access permits, and floodplain development permits, and the Floodplain Administrator for Mills County

(325) 648-2222

Mills County Courthouse, 1011 4th Street, Goldthwaite, TX 76844

Online permits →

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 Mills County, Texas?

No. Texas counties generally have no authority to require a permit or prior approval before you build a home in an unincorporated area, and that includes Mills County1. Texas law lets a narrow set of counties opt into fire-code or residential-code permitting, but only counties over a 250,000 population (or adjacent to one), or counties near an international border that pass their own adoption order, can use it9. No official record shows Mills County has adopted either program, so treat this as unconfirmed rather than assume state code inspections apply here. Industrialized housing and manufactured homes are a separate track, regulated directly by the state rather than the county.

Who handles permits in Mills County, since there's no building department?

Mills County has no building or zoning department, so most land-use paperwork routes through one place: the County Judge's office at the Mills County Courthouse in Goldthwaite4. Septic (OSSF) permit applications, county-road driveway/access permit applications, and floodplain development permit applications are all submitted there10811. The County Judge also serves as Mills County's Floodplain Administrator, reviewing, approving or denying floodplain development permits11. For anything not covered here, call the County Judge's office first.

Does Mills County have zoning?

No. Texas grants county zoning power only to specific, legislatively named areas, and Mills County isn't one of them, so the county has no zoning ordinance and no zoning districts25. Because the county has no zoning authority, it sets no minimum dwelling size, no minimum lot size, no setbacks, no lot-coverage limit and no building-height limit anywhere in unincorporated Mills County3. That's a legal consequence of state law, not a gap in local records: it applies countywide unless you're inside the City of Goldthwaite or another incorporated town, which can and do set their own rules.

How do septic (OSSF) permits work in Mills County?

An on-site sewage facility (septic) permit is required before you build, and Mills County itself is the local permitting authority, acting as TCEQ's authorized agent12. Applications go to the County Judge's office with a nonrefundable $335 application/inspection fee, current as of September 1, 202564. Once installed, contact the county's on-site sewage inspector at least five working days before you want the inspection6. Statewide, a tract of 10 acres or more can qualify for a septic-permit exemption if a licensed site evaluator or engineer signs off, the OSSF serves a single-family home, and every part of the system sits at least 100 feet from the property line13. Soils are tight here: only about 5.9% of Mills County's land has soils without severe limits for a conventional drain field, so plan for an engineered or alternative system on most parcels14.

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

Yes, county rules don't restrict it: because Mills County has no zoning authority, there is no county rule limiting RV occupancy, tiny-home occupancy or manufactured-home placement on private land in unincorporated Mills County3. Accessory dwellings are likewise unrestricted by county rule3. That freedom is about zoning only; it doesn't remove your septic, driveway or floodplain-permit obligations, which apply regardless of what kind of dwelling you put on the land11. If you're inside Goldthwaite or another incorporated city, that city's own rules take over instead.

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

  1. Confirm the parcel is unincorporated, outside Goldthwaite or any other city with its own permitting rules2.
  2. Get a site evaluation for your OSSF (septic) early, since most of the county's soil isn't suited to a conventional drain field, and apply through the County Judge's office with the $335 fee46.
  3. If your tract is 10 acres or more, ask whether you qualify for the state's septic-permit exemption before you apply13.
  4. If your driveway will connect to a county road, submit a driveway/access permit and the $50 fee to the County Judge's office before starting work8.
  5. If your parcel is in a mapped flood hazard area, get a Floodplain Development Permit from the County Judge's office before you build11.
  6. Because Mills County has no zoning or building-permit process, keep your septic permit, driveway permit and any floodplain paperwork on file in case a lender or insurer asks1.

What to check before you buy land in Mills County

Soils and septic: under 6% of Mills County land is free of severe limitations for a conventional septic field, so budget for a site evaluation and possibly an engineered system before you commit to a parcel14. Terrain: almost 95% of the county sits at 15% slope or less, which is gentle building ground, though the land is mostly open rather than wooded1516. Flood: a Floodplain Development Permit is required for construction in Mills County's mapped flood hazard areas, so check flood status with the County Judge's office before you buy11. Access: any new driveway onto a county road needs a $50 permit and 48-hour notice to the County Commissioner before work starts, and a driveway onto a state highway needs a separate TxDOT permit817. Taxes: the effective property tax rate is about 0.9%, with a median annual bill near $1,7621819.

Watch-outs

  • No official record shows Mills County has adopted Texas's optional residential building-code program under Local Government Code Chapter 2339; don't assume state building-code inspections apply here, and confirm with the County Judge's office before you build4.
  • Short-term rental rules for Mills County were not found on an official county page; check with the County Judge's office before you plan to rent out a property4.

Sources

  1. Texas Local Government Code Chapter 233 (County Regulation) (2026 county census)
  2. Texas Local Government Code Chapter 231 (County Zoning Authority) (2026 county census)
  3. Texas law on county zoning and building authority
  4. Mills County Judge's Office (millscountytx.gov)
  5. Local Government Code Chapter 231, County Zoning Authority (Texas statewide rule), quoted and re-checked
  6. Septic System Permits, quoted and re-checked
  7. Getting a Permit for an OSSF - Such as a Septic System, quoted and re-checked
  8. Mills County Road Access Policy, quoted and re-checked
  9. Local Government Code Chapter 233, County Regulation of Housing and Other Structures (Texas statewide rule), quoted and re-checked
  10. Flood Damage Prevention Court Order, quoted and re-checked
  11. Flood Damage Prevention Court Order, quoted and re-checked
  12. TCEQ - Getting a Permit for an OSSF (Septic System) (2026 county census)
  13. Getting a Permit for an OSSF - Such as a Septic System (Texas statewide rule), quoted and re-checked
  14. Share of soils without severe limits for a conventional septic drain field (USDA SSURGO): Bolthole Index county data
  15. Share of land at 15% slope or less: Bolthole Index county data
  16. Wooded share of land: Bolthole Index county data
  17. Section 4: Driveway Permits, Design, and Materials (Texas statewide rule), quoted and re-checked
  18. Effective property tax rate: Bolthole Index county data
  19. Median property tax bill: Bolthole Index county data

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.

Found land here? Start a Property Hunt →

County locator

Mills County in Texas

70
County map
Mills County highlighted among the Texas counties · colored by Index score

How Mills County scores

Seclusion77100% ev.
Self-Sufficiency3996% ev.
Admin Boringness91100% ev.
Durability44100% ev.
Property Autonomy71100% ev.
Carry Cost7296% ev.

Evidence strength: 99%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$396kTypical home
0.9%Property tax
$3,731Land / acre
30.8"Annual rain
29.7% of yrsSevere drought
33.5 / yr (+22.3)Mid-century 100°F days
28.6 daysMid-century dry spell
1.86" (+5.1%)Mid-century 1-day rain
1.38×Wildfire change factor
100%Forward climate coverage
$2,137Home insurance / yr
0.1% / yrInsurance growth
0%Nonrenewal rate
single ZIP shrunk to state medianInsurance basis
1,319,168People within 2 hr
4,844Radius comparison (15 mi)
6.1People / sq mi
0%Federal land
94.9%Land at 15% slope or less
5.9%Septic soil without severe limits
27,293 acWorkable land screen
16.8%Wooded land
9.9 tonsBiomass / forest ac
65.6°FAvg temp

Scout Mills County

Camp here before you commitBook a few nights nearby on Hipcamp →Already own land here?Earn money hosting campers — get $100 when you become a Hipcamp host →

Some links are affiliate or referral links — we may earn a commission, at no cost to you.

Property hunt

Find land. Bring the promising ones back.

Search live inventory elsewhere, then cost and vet each candidate here. No copied listings, account, or paid data feed.

View your full hunt →
ZillowLand & lotsRealtor.comLand listingsLandSearchRural & vacant land

Each button opens a current land search for Mills County. Listing sites control their own results and filters.

Analyze a property
Add setup-cost allowances

Use rough quotes or placeholders. Blank fields count as $0.

Working estimate

—land + entered setup costs
Asking $ / acre
—
Setup allowance
—
All-in $ / acre
—

A planning estimate, not a valuation or contractor quote. The USDA benchmark includes farm land and buildings; it is context, not a parcel comp.

Before an offer

Parcel due diligence

0/8 checked

Saved properties and checklist progress stay on this device. Bolthole Index does not receive them.

Answers from the rulebook for Mills County

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

Mills County rules

  • Zoning districts · by state lawNo county rule

    Unincorporated Mills County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Mills County has no zoning ordinance. The county legal census found no county zoning ordinance, citing statutes.capitol.texas.gov.

    • 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.”
  • Minimum dwelling size · by state lawNo county rule

    Unincorporated Mills County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Mills County has no zoning ordinance. The county legal census found no county zoning ordinance, citing statutes.capitol.texas.gov.

    • 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.”
  • Minimum lot size · by state lawNo county rule

    Unincorporated Mills County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Mills County has no zoning ordinance. The county legal census found no county zoning ordinance, citing statutes.capitol.texas.gov.

    • 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.”
  • Setbacks · by state lawNo county rule

    Unincorporated Mills County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Mills County has no zoning ordinance. The county legal census found no county zoning ordinance, citing statutes.capitol.texas.gov.

    • 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.”
  • Lot coverage · by state lawNo county rule

    Unincorporated Mills County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Mills County has no zoning ordinance. The county legal census found no county zoning ordinance, citing statutes.capitol.texas.gov.

    • 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.”
  • Building height · by state lawNo county rule

    Unincorporated Mills County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Mills County has no zoning ordinance. The county legal census found no county zoning ordinance, citing statutes.capitol.texas.gov.

    • 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.”
  • Living in an RV · by state lawNo county rule

    Unincorporated Mills County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Mills County has no zoning ordinance. The county legal census found no county zoning ordinance, citing statutes.capitol.texas.gov.

    • 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.”
  • Camping on your land · by state lawNo county rule

    Unincorporated Mills County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Mills County has no zoning ordinance. The county legal census found no county zoning ordinance, citing statutes.capitol.texas.gov.

    • 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.”
  • Tiny homes · by state lawNo county rule

    Unincorporated Mills County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Mills County has no zoning ordinance. The county legal census found no county zoning ordinance, citing statutes.capitol.texas.gov.

    • 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.”
  • Manufactured homes · by state lawNo county rule

    Unincorporated Mills County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Mills County has no zoning ordinance. The county legal census found no county zoning ordinance, citing statutes.capitol.texas.gov.

    • 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.”
  • Accessory dwellings · by state lawNo county rule

    Unincorporated Mills County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Mills County has no zoning ordinance. The county legal census found no county zoning ordinance, citing statutes.capitol.texas.gov.

    • 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.”
  • Septic inspectionRequired

    Mills County OSSF applications and installations.

    • The applicant must contact the Mills County on-site sewage inspector at least five working days before the desired inspection date.
    • The county application/inspection fee is $335.00 as of 9/1/2025.
    • Applications are submitted to the County Judge's office and fees are nonrefundable.

    advance notice: >= 5 working days (Before the desired inspection date) · application/inspection fee: 335 USD (As of 9/1/2025)

    “at least five (5) working days prior to desired inspection date.”
  • Driveway accessLimited

    New or revised private, public, and commercial entrances onto Mills County roads, and subdivision entrances subject to county subdivision regulations.

    • The application is for securing or changing access to the owner's property, not for parking or servicing vehicles on rights of way.
    • The application and fee must be submitted to the County Judge's office.
    • No right-of-way construction may begin before a fully executed permit and 48-hour notice to the County Commissioner.
    • Drainage impacts must be coordinated with and approved by the County Commissioner.
    • For subdivisions, entrances onto public roads are limited to one per lot and driveway culverts are required for all entrances.

    access driveway permit fee: 50 USD · driveway angle from County Road axis: 75 to 90 degrees degrees · minimum culvert spacing: >= 125 feet (The policy states culverts shall be no less than 125 feet from another culvert.)

    “No construction work on the driveway or entrance shall be undertaken on the right of way until a fully executed driveway permit has been received”
  • Building in a floodplainRequired

    Development in areas subject to Mills County's floodplain management order, including construction, substantial improvements, placement of manufactured homes, and subdivision proposals in flood hazard areas.

    • A Floodplain Development Permit is required to ensure conformance with the order.
    • The Floodplain Administrator reviews, approves, or denies development-permit applications.
    • Applications may require scaled plans, elevations, floodproofing information for nonresidential structures, professional certification, and descriptions of watercourse or drainage alterations.
    • New construction and substantial improvements in areas of special flood hazards must satisfy the order's anchoring, flood-damage-resistant materials, utilities, sewage-system, and elevation requirements.
    • Variances are subject to the order's appeal-board procedures and stated exceptions, including certain historic structures, small lots, and functionally dependent uses; variances may not be issued within a designated floodway if the variance would increase flood levels.
    “A Floodplain Development Permit shall be required to ensure conformance with the provisions of this order.”
  • Permit feesVariable (with conditions)

    Mills County subdivision, on-site sewage facility, and county-road driveway-access permits.

    • The subdivision fee schedule states that it is effective January 1, 2022.
    • The septic page states that the application/inspection fee is $335.00 as of September 1, 2025.
    • The county-road access policy was amended November 13, 2023 and requires a $50 permit fee; a preferred county-installed culvert may require an additional $1,500 fee, with possible higher charges for oversized entrances or unusual terrain.

    OSSF application/inspection fee: 335 USD (As of 2025-09-01) · Preliminary Plat fee: $300 + $100 per lot; $1,000 minimum USD (Effective 2022-01-01) · Final Plat fee: $500 + $50 per lot; $1,000 minimum USD (Effective 2022-01-01) · County-road driveway-access permit fee: 50 USD

    “Platting Services Effective January 1, 2022 Preliminary Plat $300 + $100 per lot ($1,000 Minimum Fee) Final Plat $500 + $50 per lot ($1,000 Minimum Fee)”
  • Permit processPartial

    Published Mills County processes for floodplain development, OSSF installation, county-road driveway access, and subdivision platting; no general countywide residential building-permit process was established by the reviewed sources.

    • Floodplain permits are administered by the Mills County Judge as Floodplain Administrator.
    • OSSF applications are submitted to the County Judge's office and require inspection coordination at least five working days before the desired inspection date.
    • County-road driveway work on the right of way may not begin until a fully executed permit is received and 48-hour notice is given to the County Commissioner.
    • Subdivision applications have separate preliminary and final plat procedures and fee requirements.
    “Applications are to be turned into the County Judge's office and must be accompanied by $335.00 application/inspection fee.”
  • Building permitNot required

    Texas counties have no general authority to require building permits or prior approval for new residential construction in unincorporated areas; LGC Chapter 233's permissive county building-code authority does not grant prior-approval authority.

    Texas Local Government Code Chapter 233 (County Regulation) ↗Scouted from the county site, not yet independently re-checked

  • County-wide zoningAbsent

    Texas counties generally have no zoning authority in unincorporated areas; Chapter 231 grants zoning power only to specific legislatively designated counties (not Mills County).

    Texas Local Government Code Chapter 231 (County Zoning Authority) ↗Scouted from the county site, not yet independently re-checked

Texas rules that apply here

  • Owner-builder exemptionConditional

    A homeowner installing an on-site sewage facility serving the homeowner's single-family residence in Texas, including Mills County.

    • Whether the homeowner may install the OSSF depends on whether the permitting authority allows it under local requirements.
    • The homeowner must have the knowledge, skills, and equipment to perform the work.
    • The OSSF must serve a single-family dwelling that the homeowner owns.
    • The homeowner must own the property.
    • No part of the property may be developed for sale or lease.
    • All permitting, construction, and maintenance requirements of the permitting authority must be met.
    • Some systems may not be purchased by a homeowner because they must be installed by a factory representative.
    • If another person assists with installation, that person must generally be a licensed installer, subject to the stated exceptions for licensed electricians and persons delivering and setting treatment or pump tanks.
    “This depends on whether the permitting authority allows this in their local requirements. Otherwise yes, provided you have the knowledge, skills, and equipment to do so AND: the OSSF is for a single family dwelling that you own, you also own the property, no part of the property will be developed for sale or lease, all permitting, construction, and maintenance requirements of the permitting authority are met.”
  • 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:”
  • 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.”
  • 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”:”
  • 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.”
  • 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.”

Still unanswered

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

  • Inspections — Inspections for new residential construction in unincorporated Mills County.
  • Certificate of occupancy — Certificates of occupancy for residential buildings in Mills County.
  • Local zoning — Aggregate local zoning status across Mills County, including incorporated municipalities and unincorporated areas; this is not a finding that the county administers municipal ordinances.
  • Mandatory utility hookup — Water and wastewater utility connection requirements in Mills County, Texas.
  • Short-term rentals — Short-term rentals in Mills County, Texas.

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 Mills County, Texas

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

Mills County scores 70/100 on the Bolthole Index, a strong county profile. Its strengths: low administrative friction for a quiet rural property and sparse surroundings — about 4,844 people within 15 miles. Watch-outs: workable self-sufficiency basics (30.8″/yr rainfall).

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

Mills 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 Mills County OSSF program (TCEQ authorized agent) under Tex. Health & Safety Code Ch. 366 / 30 TAC 285. Owner-builders may act as their own contractor to build their home. 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 Mills County?

Living in an RV on your own land in Mills County is allowed: Unincorporated Mills County: no county rule sets this, because Texas law gives zoning power only to certain counties, and Mills County has no zoning ordinance. The county legal census found no county zoning ordinance, citing statutes.capitol.texas.gov. 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 Mills County, Texas?

Land in Mills County runs about $3,731 per acre, based on the latest county data.

What is the water situation in Mills County?

Mills County gets about 30.8" of rain a year, with severe drought in roughly 29.7% of years.

How remote is Mills County?

A typical private-land location has about 4,844 people within 15 miles and 3,565,973 within 100 miles. These radius catchments are the published fallback where road routing is unavailable.

Off-grid gear

Going off-grid in Mills County means bringing your own water and power. The kit we’d start with:

These are affiliate links — we may earn a commission, at no cost to you. As an Amazon Associate, Bolthole Index earns from qualifying purchases.

How Mills compares in Texas

Compare side-by-side →See all 254 Texas counties ranked →