Bolthole Index

Franklin County, Texas

Zoning, building permits and septic in the Town of Mount Vernon, Texas

The Town of Mount Vernon, Texas has its own zoning ordinance, effective April 14, 2025, that covers town limits and the extraterritorial jurisdiction1. Building permit applications and a certificate of occupancy run through the town's Zoning Official2. Septic permits in Franklin County are issued by the county Septic Inspector3; we could not confirm who handles septic inside town limits.

At a glance

Zoning
Yes: town ordinance, also reaching the extraterritorial jurisdiction1
Building permit
Applications are tied to a certificate of occupancy issued by the Zoning Official; adopted building code not confirmed2
RV living
Large RVs (over 22 feet) in residential districts may not be used for living or sleeping4
R-1 minimum lot
1 acre, 100 feet wide, 40 feet of road frontage5
R-1 setbacks
Front 40 ft, rear 20 ft, side 5 to 10 ft6
Septic
Franklin County Septic Inspector for the county; inside town limits not confirmed3

Who to call

Zoning

Town of Mount Vernon Zoning Official

Zoning compliance, certificates of occupancy and building permit applications under the town zoning ordinance

Septic permits

Franklin County Septic Inspector & Designated Representative

On-site sewage facility (septic) permits and inspections for Franklin County

(903) 537-8346

204 Texas HWY 37, Mount Vernon, TX 75457

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 Town of Mount Vernon means bringing your own water and power. The kit we’d start with:

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Does Mount Vernon, Texas have zoning, and what does it mean for RVs and lot size?

Yes. The Town of Mount Vernon applies its zoning ordinance to all public and private use and development of property inside town limits, and to its extraterritorial jurisdiction to the extent state or federal law allows1. The current ordinance became effective April 14, 20251. The official zoning map is part of the ordinance, and the town keeps electronic zoning map files7.

Rules depend on the district. In the single-family Residential Estates (R-1) district, the minimum lot is 1 acre, 100 feet wide, with 40 feet of road frontage5. R-1 setbacks are 40 feet in front, 20 feet in the rear and 5 to 10 feet on the sides6. In the Agricultural Homesteads (AG) district, one detached accessory dwelling is allowed per dwelling unit8.

For RVs, a large recreational vehicle (over 22 feet) parked or stored in a residentially zoned district may not be used for housekeeping, living or sleeping4. We could not confirm rules for tiny homes or temporary camping inside town limits; ask the Zoning Official.

Do you need a building permit in Mount Vernon, Texas, and who issues it?

The town's zoning ordinance provides for building permit applications and a fee schedule adopted by the Council9. A certificate of occupancy, issued by the Zoning Official, is required before a new or altered building is occupied, and the certificate application is made together with the building permit application2. Vacant land used for agriculture is excepted from the certificate requirement, but that exception does not excuse other ordinance requirements10.

We could not confirm which building code the town has adopted, whether it inspects buildings, or whether an owner-builder exemption applies inside town limits. Ask the Zoning Official at Mount Vernon town hall before you draw plans. Electrical owners who live in their own dwelling are exempt from state electrician licensing, but that does not exempt local permits or inspections11.

How do septic permits work inside Mount Vernon, Texas?

Franklin County administers on-site sewage facility permits under an order approved by TCEQ, and the county Septic Inspector is the authorized agent3. The county lists residential septic permit fees of $375 and commercial fees of $55012. A permit and approved plan are generally required13.

A 10-acre exemption exists only for a single-family dwelling on a tract of at least 10 acres where every other state condition is also met, including keeping all septic parts at least 100 feet from the property line13. Most town lots are far smaller, so plan on a permit. We could not confirm who administers septic permits for lots inside town limits, or whether public sewer is available at a given lot, so call the Franklin County Septic Inspector and the town before you buy14. Soils matter too: only about 5.3% of the county's soils rate as not limited for a conventional drain field, so expect a site evaluation and possibly an engineered system15.

Building a home in Mount Vernon, Texas: the steps, in order

  1. Find the zoning district of your lot on the town's official zoning map and read that district's lot size and setback rules7.
  2. Confirm lot rules: in R-1, the minimum lot is 1 acre5.
  3. If you are dividing land, lots created or modified must comply with the zoning ordinance16.
  4. Apply to the town for a building permit and certificate of occupancy together, and pay fees in full before review9.
  5. Get the septic permit from the Franklin County Septic Inspector, or confirm sewer service with the town3.
  6. If the driveway meets a state highway, submit TxDOT Form 1058 before building on the right of way17.
  7. Obtain the certificate of occupancy before moving in2.

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

The town's rules apply inside town limits and its extraterritorial jurisdiction; land outside is covered on the Franklin County page. Unincorporated Franklin County has adopted no county zoning ordinance18.

Flood and water: inside the City of Mount Vernon, floodplain coordination goes to the Mount Vernon floodplain administrator, while the Franklin County floodplain administrator covers unincorporated land19. Private wells may need a permit if the property lies within a groundwater conservation district; we could not confirm this for specific parcels20. Franklin County's effective property tax rate is 0.9%21.

Watch-outs

  • We could not confirm the building code, inspection requirements or owner-builder rules that apply inside Mount Vernon town limits; ask the Zoning Official at town hall22.
  • The zoning ordinance also applies in the extraterritorial jurisdiction, so land just outside town limits may still be covered1.
  • We could not confirm who issues septic permits inside town limits; confirm with the Franklin County Septic Inspector before buying3.
  • Agricultural use of vacant land is excepted only from the certificate of occupancy requirement, not from other town rules10.

Sources

  1. City of Mount Vernon Zoning Ordinance (Town of Mount Vernon), quoted and re-checked
  2. City of Mount Vernon Zoning Ordinance (Town of Mount Vernon), quoted and re-checked
  3. Septic Inspector & Designated Representative, quoted and re-checked
  4. City of Mount Vernon Zoning Ordinance (Town of Mount Vernon), quoted and re-checked
  5. City of Mount Vernon Zoning Ordinance (Town of Mount Vernon), quoted and re-checked
  6. City of Mount Vernon Zoning Ordinance (Town of Mount Vernon), quoted and re-checked
  7. City of Mount Vernon Zoning Ordinance (Town of Mount Vernon), quoted and re-checked
  8. City of Mount Vernon Zoning Ordinance (Town of Mount Vernon), quoted and re-checked
  9. City of Mount Vernon Zoning Ordinance (Town of Mount Vernon), quoted and re-checked
  10. City of Mount Vernon Zoning Ordinance (Town of Mount Vernon), quoted and re-checked
  11. Exemptions to Electrician Licensing (Texas statewide rule), quoted and re-checked
  12. Septic Inspector & Designated Representative, quoted and re-checked
  13. Franklin County Texas — Septic Inspector & Designated Representative, quoted and re-checked
  14. Franklin County Septic Inspector & Designated Representative (co.franklin.tx.us)
  15. 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
  16. City of Mount Vernon Zoning Ordinance (Town of Mount Vernon), quoted and re-checked
  17. Section 4: Driveway Permits, Design, and Materials (Texas statewide rule), quoted and re-checked
  18. Texas law on county zoning and building authority
  19. Determination of No Effect — City of Mount Vernon, Franklin County, Texas, quoted and re-checked
  20. Groundwater Regulation for Private Well Owners, quoted and re-checked
  21. Effective property tax rate: Bolthole Index county data
  22. Town of Mount Vernon Zoning Official (core-docs.s3.us-east-1.amazonaws.com)

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 Town of Mount Vernon

Town of Mount Vernon’s own rules

  • Certificate of occupancyRequired

    Buildings erected, reconstructed, altered, or enlarged inside Mount Vernon town limits, and use of vacant land other than agricultural use.

    • The certificate must state compliance with building and health laws and the zoning ordinance.
    • A certificate is not required for existing nonconforming uses, lots, or structures, although it may be applied for.
    • Certificate application is coincident with a Building Permit application.
    “No vacant land shall be occupied or used, except for agricultural purposes, and no building hereafter erected, reconstructed, altered, or enlarged, shall be occupied or used until a certificate of occupancy shall have been issued by the Zoning Official stating that the building or proposed use of the building or premises complies with the building and health laws and with the provisions of the Zoning Ordinance.”
  • Local zoningPresent (with conditions)

    Public and private use and development of property inside Mount Vernon town limits.

    • The ordinance also applies in the extraterritorial jurisdiction to the maximum extent state or federal law allows.
    • Ordinance No. 2025-03 became effective April 14, 2025.
    “The provisions of the Zoning Ordinance apply to all public and private use and development of properties within the corporate limits and extraterritorial jurisdiction of the City of Mount Vernon, to the maximum extent allowed by state or federal law, and except as expressly stated in the Zoning Ordinance.”
  • Zoning districtsPublished (with conditions)

    Zoning districts inside Mount Vernon town limits.

    • The official zoning map is part of the ordinance.
    • The City maintains electronic mapping or GIS files with approved zoning amendments.
    “The districts aforesaid, and the boundaries of such districts, shall be as shown upon the map attached hereto and made a part of this ordinance, said map being designated “Official Zoning Map,””
  • Agricultural exemptionConditional

    Agricultural use of vacant land inside Mount Vernon town limits.

    • The stated exception is to the certificate-of-occupancy requirement for occupancy or use of vacant land; it does not state an exemption from other ordinances.
    “No vacant land shall be occupied or used, except for agricultural purposes”
  • Subdividing landRegulated (with conditions)

    Lots created or modified inside Mount Vernon town limits.

    • All lots created or modified must comply with the zoning ordinance.
    “All lots created or modified must comply with the Zoning Ordinance.”
  • Permit feesPublished (with conditions)

    Zoning-related building-permit, certificate-of-occupancy, zoning-compliance, appeal, and zoning-change applications inside Mount Vernon town limits.

    • The Council adopts the fee schedule.
    • No application or appeal subject to the schedule is reviewed or processed until fees are paid in full.
    • Fee-schedule changes require Council adoption.
    “The fee schedule shall apply to and a collection procedure shall be provided for applications for building permits and for certificates of occupancy and zoning compliance, for applications and appeals to the City Council, for applications for zoning change, and for other matters pertaining to this ordinance.”

Rules another office applies inside Town of Mount Vernon

Town of Mount Vernon does not set these itself; the county, a health district or the state does, and they apply to every address inside its limits.

  • Minimum lot sizeSpecified

    Residential Estates (R-1) District, the single-family residential district, inside Mount Vernon town limits.

    minimum lot area: 1 acre (R-1 District) · minimum lot width: 100 feet (R-1 District) · minimum lot road frontage: 40 feet (R-1 District)

    “Minimum lot area: 1 Acre Minimum lot width: 100 ft Minimum lot road frontage: 40 ft”
  • SetbacksSpecified

    Residential Estates (R-1) District inside Mount Vernon town limits.

    front yard setback: 40 feet (R-1 District) · rear yard setback: 20 feet (R-1 District) · side yard setback: 5 - 10 feet (R-1 District)

    “Minimum front yard setback: 40 ft Minimum rear yard setback: 20 ft Minimum side yard setback: 5 - 10 ft”
  • Living in an RVProhibited

    Large recreational vehicles parked or stored in residentially zoned districts inside Mount Vernon town limits.

    • A large recreational vehicle is a self-propelled or towable vehicle exceeding 22 feet in length.
    • The restriction concerns RVs parked or stored in residentially zoned districts.

    large RV threshold: > 22 feet

    “All large recreational vehicles parked or stored in a residentially zoned district must meet the following requirements. [...] may not be used for housekeeping, living, or sleeping quarters.”
  • Accessory dwellingsAllowed (with conditions)

    Agricultural Homesteads (AG) District inside Mount Vernon town limits.

    • One detached accessory dwelling is permitted per dwelling unit.

    accessory dwellings: per 1 per dwelling unit (AG District)

    “Dwellings, detached accessory [1 per DU]”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Town of Mount Vernon or Franklin County directly.

  • Owner-builder exemption — Owner-builder work inside Mount Vernon town limits.
  • Building code adopted — Building-code adoption inside Mount Vernon town limits.
  • Inspections — Building inspections inside Mount Vernon town limits.
  • Minimum dwelling size — Single-family dwellings inside Mount Vernon town limits.
  • Camping on your land — Temporary camping on private land inside Mount Vernon town limits.
10 more unanswered
  • Tiny homes
  • Who permits septic
  • Septic permit
  • Septic inspection
  • Off-grid sanitation
  • Well permit
  • Mandatory utility hookup
  • Driveway access
  • 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.

Unanswered questions are usually a sign that Town of Mount Vernon publishes no rule on the point, not that none exists. Franklin County’s page lists the county offices to call.

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