Building permits, zoning and septic rules in Somervell County, Texas

At a glance

Building permit

No general county building permit found outside the City of Glen Rose; ask the county before relying on that¹

Zoning

None in unincorporated Somervell County³²

Septic (OSSF)

County permit required through the OSSF office before you build⁴⁵

RV, tiny home & camping

No zoning-based restriction on unincorporated land²

Minimum lot size (new subdivision)

2 acres net with septic, 1 acre net with public water⁷

Driveway on a state highway

TxDOT Form 1058 permit required before construction⁸⁹

Water well

Non-exempt wells need a Prairielands Groundwater Conservation District permit⁶

Who to call

Contact details are copied from each office’s official page and were checked against it on October 10, 2026.

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

Unincorporated Somervell County appears to have no building department and no building-permit requirement for ordinary construction: the county's own site addresses on-site sewage permitting but nothing broader, and we could not find a county ordinance establishing general building permits, so confirm with the OSSF office or Commissioners Court before you start¹. Texas gives some large counties authority to adopt a fire code covering commercial buildings, public buildings and multifamily dwellings of four or more units in unincorporated areas, but only for a county with a population over 250,000 or adjacent to one — Somervell County's own population, about 9,888, is far below that threshold¹⁰¹¹. Inside the incorporated City of Glen Rose, a separate building-permit and zoning process applies, run by the city rather than the county¹. If you're placing a factory-built or modular unit rather than site-building, Texas's Industrialized Housing and Buildings program sets statewide construction-code standards for those units wherever you build¹².

Who handles septic, floodplain and road matters in Somervell County?

There's no county building department to contact, but three offices matter for rural land in Somervell County¹. Septic (OSSF) permits go through the county's On-Site Sewage Facility office in Glen Rose, which also serves as the county's Floodplain Administrator¹³¹⁴. County road and driveway questions for county-maintained roads go to Road & Bridge Maintenance, also based in Glen Rose¹⁵. New subdivisions outside Glen Rose need Commissioners Court approval of the plat, with the County Health Unit's Designated Representative — the same OSSF office — reviewing the plat for sanitation before that happens¹⁶¹⁷.

Does Somervell County have zoning?

Unincorporated Somervell County has no zoning: Texas counties don't have general zoning power, and Somervell County has not adopted a zoning ordinance for its unincorporated area³. Because the county has no zoning authority here, it sets no minimum dwelling size, no setbacks, no lot-coverage limit and no building-height limit for unincorporated land, and it publishes no zoning districts². That's different from the incorporated City of Glen Rose, which does zone within its own limits and regulates uses like manufactured homes district by district¹⁸. Even without zoning, a new subdivision outside Glen Rose still has to meet the county's own lot-size rules: 2 acres net per lot where it will use on-site sewage, or 1 acre net per lot where it will have public water⁷.

How do septic permits work in Somervell County?

Septic systems (OSSFs) in unincorporated Somervell County are permitted by the county itself, acting as the state's authorized agent, through the On-Site Sewage Facility office in Glen Rose⁴¹³. Almost every OSSF needs a permit before construction, installation, repair or extension, for a new house or a replacement of a failed system alike⁵. Texas does carve out an exemption for larger tracts: a single-family home on at least 10 acres can skip the OSSF permit if a licensed site evaluator confirms no nuisance or groundwater-pollution risk, every part of the system sits at least 100 feet from the property line, effluent stays on your property, and the house is the only dwelling on the tract¹⁹. Soils here are a mixed bag: about 19.1 percent of Somervell County's soils are free of severe limitations for a conventional septic drain field, so plenty of land will perk, but plan on a site evaluation before you assume yours will²⁰.

Water supply has its own permit: all non-exempt wells in Somervell County must get a permit from the Prairielands Groundwater Conservation District, and a new well gets an Operating Permit.⁶

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

Because unincorporated Somervell County has no zoning ordinance, the county places no zoning-based restriction on living in an RV, a tiny home or a temporary camping setup on your own unincorporated land, and the same is true for adding an accessory dwelling². That's a real answer, not just an absence of information: Texas law simply doesn't give the county zoning power to restrict those uses here². It isn't a blanket exemption from everything else, though. Any habitable structure, an RV included if you're living in it full time, still needs a wastewater system that meets state and county OSSF rules, and a new lot created for that purpose has to meet the county's minimum lot-size chart²¹⁷. This guide could not confirm a county short-term-rental rule, so if you plan to rent the RV or tiny home out rather than live in it yourself, check with the county directly¹³.

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

First, confirm your parcel is outside the City of Glen Rose, since inside city limits you'd need a city building permit and follow city zoning instead of the rules in this guide¹. Second, contact the county's On-Site Sewage Facility office early for your septic permit; almost every OSSF needs one before construction starts, unless your home sits on 10 acres or more and meets Texas's site-evaluation exemption conditions¹³⁵¹⁹. Third, if you're creating a new lot rather than buying an existing platted one, get Commissioners Court approval of your plat before construction begins; fees run $350 plus $10 per lot for a 1-5 lot subdivision, and the Court has 30 days to act¹⁷. Fourth, size your lot to the chart: 2 acres net per lot with on-site sewage, or 1 acre net per lot with public water⁷. Fifth, if your driveway will connect to a state highway, submit TxDOT Form 1058 to the local district office and get your permit before any construction on the right of way⁹. Finally, ask the county's Floodplain Administrator — the same OSSF office — whether your land sits in a mapped flood zone before you build¹⁴.

What to check before you buy land in Somervell County

Somervell County is gentle and largely private: 91.4 percent of the county sits at 15 percent slope or less, 40.1 percent is wooded, and none of the county is federal land, so most of what you see on a map is potentially buildable and privately held²²²³²⁴. Water is a real constraint: the county averages only about 35.8 inches of rain a year and has been in severe drought roughly 29.8 percent of years, so a private well's yield, its Prairielands Groundwater Conservation District permit and any surface-water rights are worth checking before you buy²⁵²⁶⁶. At about 9,888 people and 53.1 people per square mile, Somervell is more settled than many rural counties, and the nearest city of 100,000 or more is about 47 miles away¹⁰²⁷²⁸. Property taxes run a bit higher than many rural counties, with an effective rate near 1 percent and a median annual bill around $2,452 against a typical home value near $416,622²⁹³⁰³¹.

Watch-outs

• Somervell County publishes no owner-builder exemption from any building-permit or inspection process; since the county has no general building-permit program to begin with, this mostly matters if you're building inside Glen Rose city limits, where it's worth asking the city directly³².
• The 'no zoning-based restriction' answer for RVs, tiny homes and accessory dwellings covers only what county zoning would otherwise control; no official source confirms how manufactured homes or short-term rentals are treated outside Glen Rose, so ask the OSSF/Floodplain office about your specific plan¹³.
• This guide could not confirm whether Somervell County requires a certificate of occupancy for any structure; no official county page addresses it, and the OSSF/Floodplain office is this guide's best starting point for a parcel-specific answer¹³.

Sources

1. Somervell County - On-Site Sewage Facility (OSSF) (2026 county census)
2. Texas law on county zoning and building authority
3. Texas Local Government Code Chapter 211 (2026 county census)
4. Subdivision Rules Somervell County, Texas (2026 county census)
5. Basics for Septic Systems, quoted and re-checked
6. About - Prairielands Groundwater Conservation District, quoted and re-checked
7. Rules & Regulations for Subdivisions, Somervell County, Texas, quoted and re-checked
8. Section 4: Driveway Permits, Design, and Materials (Texas statewide rule), quoted and re-checked
9. Section 4: Driveway Permits, Design, and Materials (Texas statewide rule), quoted and re-checked
10. County population: Bolthole Index county data
11. Local Government Code Chapter 233, County Regulation of Housing and Other Structures (Texas statewide rule), quoted and re-checked
12. Industrialized Housing and Buildings – Adoption of New Code Editions (Texas statewide rule), quoted and re-checked
13. Somervell County On-Site Sewage Facility (OSSF) Office (somervell.co)
14. Somervell County Floodplain Administrator (same office as OSSF) (somervell.co)
15. Somervell County Road & Bridge Maintenance (somervell.co)
16. Subdivision Rules Somervell County, Texas, quoted and re-checked
17. Rules & Regulations for Subdivisions, Somervell County, Texas, quoted and re-checked
18. Appendix A Schedule of Uses, quoted and re-checked
19. Getting a Permit for an OSSF - Such as a Septic System (Texas statewide rule), quoted and re-checked
20. 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
21. Subdivision Rules Somervell County, Texas, quoted and re-checked
22. Share of land at 15% slope or less: Bolthole Index county data
23. Wooded share of land: Bolthole Index county data
24. Federal land share: Bolthole Index county data
25. Annual precipitation: Bolthole Index county data
26. Share of years in severe drought: Bolthole Index county data
27. Population density: Bolthole Index county data
28. Straight-line distance from the county center to the nearest city of 100,000+ people: Bolthole Index county data
29. Effective property tax rate: Bolthole Index county data
30. Median property tax bill: Bolthole Index county data
31. Typical home value (Zillow): Bolthole Index county data
32. Exemptions to Electrician Licensing (2026 county census)

Written October 10, 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.