According to State Law:
Add by Acts 2005, 79th Leg.,ch. 917§ 1, eff. Sept. 1, 2005
For text of sections added by Acts 2005, 79th Leg., ch. 1103, § 1. see § 214.904
Note: Pursuant to the above referenced state law, a building permit application will be APPROVED or DENIED within forty-five (45) days. However, the goal of the building department is to complete plan review and have a building permit ready to issue within ten (10) business days for one-and two-family residential and twenty (20) business days for all other development. This, however, depends on the number of applications ahead of you, re-submittal of plan corrections or other requested items (engineering, etc.), which may extend the overall time period.
Plan Submittal Procedures (PDF)