We are building in Van Zandt county and it does not have building codes, but does require septic permits.
Here is a relatively new law about building a residence where there are no inspections.
http://www.trcc.state.tx.us/Inspectors/CountyInspections.asp"As of September 1, 2008, the Texas Residential Construction Commission requires all homes built or remodeled in unincorporated areas or in cities that do not offer inspections be inspected at least three times by a fee inspector, as applicable at certain stages of construction, as outlined in subtitle F, Chapter 446 of the Texas Residential Construction Commission Act. The builder/remodeler is responsible for hiring a fee inspector such as AGTM Engineering, LLC to provide the following TRCC inspections:
The three inspections required, as applicable, include:
A foundation inspection conducted prior to the placement of concrete, also known as the pre-pour;
A framing and mechanical systems inspection conducted prior to the placement of exterior wall insulation or interior wall coverings, also known as the pre-cover or stage II and
A final inspection conducted when the home is completed."
If you build your home yourself, you are not required to have these inspections.
