Bolthole Index

Limestone County, Texas

Zoning, building permits and septic rules in Mexia, Texas

Mexia, Texas (Limestone County) requires a permit through its Building Department for all construction inside city limits1, and the city zones every lot, tract and property within those limits2. Septic permits are a separate question: we could not confirm who administers them inside the city, so ask the Limestone County OSSF office before you plan a system.

At a glance

Building permit
Required for all construction inside Mexia city limits, through the city's Building Department3
Building code
2024 International Residential Code and International Building Code, effective July 21, 20254
Zoning
City zoning ordinance covers every lot, tract and property inside city limits2
Residential lots
Minimum lot area is 6,000 to 35,000 square feet depending on the R district; maximum height 35 feet56
Septic
Not confirmed inside city limits; Limestone County is the state's authorized agent for the county7
Floodplain
Development permit required, with the city inspector as floodplain administrator8

Who to call

Building permits

City of Mexia Building Department

Building permits and inspections for construction inside Mexia city limits

254-562-4184

Septic permits

Limestone County OSSF / Environmental Office

Septic (OSSF) permits as the state's authorized agent for Limestone County

200 West State Street, Suite 101, Groesbeck, TX 76642

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

Off-grid gear

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

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Do you need a building permit in Mexia, Texas?

Yes. The City of Mexia states that "All construction activities in the city require a permit through the Building Department"13. The building official receives the applications the code requires, issues the permits and furnishes the prescribed certificates9, and inspects the premises for which permits have been issued10.

Mexia's current codes include the 2024 International Residential Code and the 2024 International Building Code, effective July 21, 20254. We could not confirm a published permit fee schedule, whether owner-builders get any exemption, or whether a certificate of occupancy is required, so ask the Building Department.

Who issues building permits in Mexia, and how do you reach them?

The City of Mexia Building Department issues building permits inside city limits; call 254-562-4184 if you are unsure whether your project needs a permit or a plan review1.

The county's no-permit answer does not apply here. Unincorporated Limestone County does not require a county building permit for ordinary residential construction, because only cities can adopt building codes11. Inside Mexia, the city's permit rules govern instead. For land outside city limits, see the Limestone County page.

Does Mexia have zoning, and what does it mean for lot size and setbacks?

Mexia has zoning. The city's ordinance, adopted July 21, 2009, says each lot, tract or property within city limits is zoned for one or more use classifications2. The published districts are Residential Divisions 1 to 3, Commercial Divisions 1 to 4, CR Divisions 1 to 2 and FI Divisions 1 to 3, and the zoning map is a separate exhibit12. Check your parcel's district with the city before you buy.

Lot size depends on the district. Residential minimum lot areas run from 6,000 to 35,000 square feet5. Front setbacks run 15 to 25 feet, side setbacks 5 to 10 feet and rear setbacks 20 to 30 feet, depending on the residential division13. Maximum residential building height is 35 feet6. Single-family dwellings and accessory living quarters are permitted in an R, Division 1 zone14.

We could not confirm Mexia's rules on RVs, tiny homes, manufactured homes, minimum dwelling size or lot coverage, so ask the Building Department.

How do septic permits work in Mexia?

We could not confirm who administers septic permits for addresses inside Mexia city limits. Limestone County is the state-authorized agent for septic systems in the county7, and a permit is required to construct, install, alter, extend or repair a system15. Contact the Limestone County OSSF office in Groesbeck and the Mexia Building Department to learn which one handles your lot16.

City sewer availability matters too: we could not confirm Mexia's rule on when a new home must connect to city water or sewer, so ask the city. Statewide, a single-family home on a tract of at least 10 acres can qualify for an exemption from septic permitting if every condition is met17. Mexia lots are usually far smaller than that.

Can you live in an RV or tiny home in Mexia?

We could not confirm it. Mexia's zoning ordinance as we reviewed it does not state a rule for living in an RV, tiny home or manufactured home, or for temporary camping. Call the Building Department at 254-562-4184 before you move anything onto a lot1. Unincorporated Limestone County is different, because the county has no zoning at all18.

Building a home in Mexia: the steps, in order

  1. Confirm the lot's zoning district and setbacks with the city12.
  2. Check whether the lot lies in a floodplain; the city requires a development permit for floodplain development8.
  3. Ask the Limestone County OSSF office whether a septic system or city sewer applies16.
  4. Apply for a building permit through the Building Department1.
  5. Schedule the inspections the building official requires10.
  6. If you divide land, get planning and zoning commission approval before recording the plat19.

What stays with Limestone County, and what to check before you buy?

Mexia's rules stop at the city limits. For land outside them, the county page covers unincorporated Limestone County: Limestone County. The city's subdivision rules reach land within one mile of the city limits19.

Limestone County's typical home value is $178,56720, and its effective property tax rate is 1.2%21. Only 14.8% of county soils are rated not limited for a conventional septic drain field, so a site evaluation is likely22.

Watch-outs

  • Inside Mexia, a city building permit is required for all construction, so a county rule of "no building permit" does not carry over3.
  • We could not confirm septic authority, permit fees, RV or tiny-home rules, or an owner-builder exemption inside Mexia city limits; call the Building Department at 254-562-41841.
  • Land within one mile of the city limits is subject to Mexia's subdivision approval before a plat is recorded19.

Sources

  1. City of Mexia Building Department (cityofmexia.com)
  2. City of Mexia Zoning Ordinance, Exhibit A (Mexia), quoted and re-checked
  3. City of Mexia Code, § 3.02.031, Building official (Mexia), quoted and re-checked
  4. City of Mexia Code, § 3.02.031, Building official (Mexia), quoted and re-checked
  5. City of Mexia Zoning Ordinance, Exhibit A (Mexia), quoted and re-checked
  6. City of Mexia Zoning Ordinance, Exhibit A (Mexia), quoted and re-checked
  7. Limestone County - OSSF Instructions (2026 county census)
  8. City of Mexia Code, § 3.05.033, Development permit required (Mexia), quoted and re-checked
  9. City of Mexia Code, § 3.02.031, Building official (Mexia), quoted and re-checked
  10. City of Mexia Code, § 3.02.031, Building official (Mexia), quoted and re-checked
  11. Official Limestone County Mitigation Plan 2014, quoted and re-checked
  12. City of Mexia Zoning Ordinance, Exhibit A (Mexia), quoted and re-checked
  13. City of Mexia Zoning Ordinance, Exhibit A (Mexia), quoted and re-checked
  14. City of Mexia Zoning Ordinance, Exhibit A (Mexia), quoted and re-checked
  15. Getting a Permit for an OSSF - Such as a Septic System, quoted and re-checked
  16. Limestone County OSSF / Environmental Office (co.limestone.tx.us)
  17. Getting a Permit for an OSSF - Such as a Septic System (Texas statewide rule), quoted and re-checked
  18. Texas law on county zoning and building authority
  19. City of Mexia Code, Chapter 10, Subdivision Regulation (Mexia), quoted and re-checked
  20. Typical home value (Zillow): Bolthole Index county data
  21. Effective property tax rate: Bolthole Index county data
  22. Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data

Written October 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.

Answers from the rulebook for Mexia

Mexia’s own rules

  • Building permitRequired

    Building work for which Mexia's adopted building code requires an application or permit, inside city limits.

    • The precise list of permit-exempt work was not established from the opened ordinance section.
    “All construction activities in the city require a permit through the Building Department.”
  • Building code adoptedAdopted (with conditions)

    Construction regulated by Mexia's building official inside city limits.

    • The opened code provision refers to the building code adopted in § 3.02.001; the specific edition was not established in the opened material.
    “Note: All current codes are effective as of July 21, 2025. (1) International Residential Code, 2024 edition. (2) International Building Code, 2024 edition.”
  • InspectionsRequired

    Premises for which Mexia building permits have been issued.

    • Inspections are performed by the building official or a duly appointed assistant; reports of recognized inspection services may be accepted after investigation of qualifications and reliability.
    “He shall examine the premises for which permits have been issued and shall make necessary inspections to see that the provisions of law are complied with and that construction is prosecuted safely.”
  • Local zoningPresent (with conditions)

    Lots, tracts, and property inside Mexia city limits.

    • The ordinance identifies its adoption date as July 21, 2009.
    “Each and every lot, tract or property within the city limits of the City of Mexia, Limestone County, Texas, shall be zoned for one or more of the use classification[s] as described in Exhibit “A” attached hereto and incorporated herein.”
  • Zoning districtsPublished (with conditions)

    Zoning districts inside Mexia city limits.

    • The published ordinance describes R Divisions 1-3, C Divisions 1-4, CR Divisions 1-2, and FI Divisions 1-3. The zoning map is incorporated as Exhibit B but is not printed in the code attachment.
    “The zoning map attached to this Ordinance as Exhibit “B” and incorporated herein shall show the initial zoning class or classes to be applied to each lot, tract and property located within the city limits of the City of Mexia, Limestone County, Texas.”
  • Minimum lot sizeDistrict specific (with conditions)

    Residential (R) zoning districts inside Mexia city limits.

    • Table 502.1 applies to Residential Zone Divisions 1, 2, and 3; subdivision rules may also apply.

    R-1 minimum lot area: 6000 to 35000 square feet (Varies by R-1 subdivisions a through d.) · R-2 minimum lot area: 6000 to 10000 square feet (Varies by R-2 subdivisions a and b.) · R-3 minimum lot area: 6000 square feet (Both R-3 subdivisions a and b.)

    “502.1 General. The minimum area, setbacks, density and maximum height shall be as prescribed in Table 502.1.”
  • SetbacksDistrict specific (with conditions)

    Residential (R) zoning districts inside Mexia city limits.

    • Table 502.1 applies by residential division and subdivision.

    front setback: 15 to 25 feet (Varies by residential division and subdivision.) · side setback: 5 to 10 feet (Varies by residential division and subdivision.) · rear setback: 20 to 30 feet (Varies by residential division and subdivision.)

    “502.1 General. The minimum area, setbacks, density and maximum height shall be as prescribed in Table 502.1.”
  • Building heightDistrict specific (with conditions)

    Residential (R) zoning districts inside Mexia city limits.

    • Accessory towers, satellite dishes, and similar structures may exceed the maximum height when approved by the code official.

    maximum building height: 35 feet (Residential Zone Divisions 1, 2, and 3 in Table 502.1.)

    “Accessory towers, satellite dishes and similar structures shall be permitted to exceed the maximum height when approved by the code official.”
  • Accessory dwellingsAllowed (with conditions)

    Accessory living quarters in Residential Division 1 zoning districts inside Mexia city limits.

    • Allowed as an accessory building to listed R-1 permitted uses; all other applicable zoning and building rules remain applicable.
    “Division 1. The following uses are permitted in an R, Division 1 zone: Single-family dwellings, public owned and operated parks, recreation centers, swimming pools and playgrounds, police and fire department stations, public and governmental services, public libraries, schools and colleges (excluding colleges or trade schools operated for profit), public parking lots, private garages, buildings accessory to the above permitted uses (including private garages and accessory living quarters), and temporary buildings.”
  • Agricultural exemptionConditional

    Agricultural land divisions inside Mexia city limits.

    • The exclusion applies only to agricultural-purpose divisions in parcels of five acres or more where no building construction is involved, and does not apply if the division includes planning or development of a new street or access easement or realignment of an existing street.

    minimum parcel size: >= 5 acres (Agricultural-purpose divisions with no building construction.)

    “Divisions of land for agricultural purposes in parcels of five (5) acres or more and where no building construction is involved shall not be included within this definition of subdivision, unless any such subdivision of five (5) acres or more includes the planning or development of a new street or access easement or realignment of an existing street.”
  • Subdividing landRegulated (with conditions)

    Subdivision plans, plats, and replats for land inside Mexia city limits.

    • City planning and zoning commission approval must occur before recording with the county clerk. Agricultural divisions in parcels of five acres or more without building construction are excluded from the definition unless they include a new street, access easement, or realignment of an existing street.
    “Before any plan, plat or replat of a subdivision or addition of land inside the city or within one (1) mile of the city limits shall be recorded with the county clerk, it shall be first approved by the city planning and zoning commission in conformance with the provisions of this chapter.”
  • Building in a floodplainRequired

    Development regulated by Mexia's flood-damage-prevention article inside city limits.

    • The city inspector is floodplain administrator. Applications may require plans in duplicate showing locations, dimensions, and elevations, plus the listed information for new or substantially improved structures and altered watercourses.
    “A development permit shall be required to ensure conformance with the provisions of this article.”
  • Permit processPartial

    Building permit applications inside Mexia city limits.

    • The opened provision establishes that the building official receives code-required applications and issues permits; it does not provide a complete application checklist.
    “The building official shall receive applications required by this code, issue permits and furnish the prescribed certificates.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Mexia or Limestone County directly.

  • Owner-builder exemption — Owner-performed residential construction inside Mexia city limits.
  • Certificate of occupancy — Occupancy of structures inside Mexia city limits.
  • Minimum dwelling size — Dwellings inside Mexia city limits.
  • Lot coverage — Lots inside Mexia city limits.
  • Living in an RV — Residential occupancy of RVs on private land inside Mexia city limits.
12 more unanswered
  • Camping on your land
  • Tiny homes
  • Manufactured homes
  • Who permits septic
  • Septic permit
  • Septic inspection
  • Off-grid sanitation
  • Well permit
  • Mandatory utility hookup
  • Driveway access
  • Short-term rentals
  • Permit fees

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.

Unanswered questions are usually a sign that Mexia publishes no rule on the point, not that none exists. Limestone County’s page lists the county offices to call.

← All of Limestone County: county rules, score and offices