Here is more information about these inspections: "The three required minimum inspections are a foundation inspection, a framing, mechanical and delivery systems inspection and a final inspection....The new county inspection requirements apply to new construction or remodeling projects that begin on or after September 1, 2008." [FROM: County Inspections FAQ (TRCC)]

What are the code requirements for these required inspections?

Every city in the State of Texas is given authority to adopt building codes, make amendments, and/or adopt ordinances to meet local concerns to the adopted building codes for their own city and its extraterritorial jurisdiction (ETJ). The law provides that in unincorporated areas of the state, the IRC and the NEC as adopted by the municipality that is the county seat of the county in which the construction is taking place, including any amendments or ordinances by that municipality, apply to the construction of the unincorporated areas of that county. The code that applies to an unincorporated area is the same code adopted by the county seat including amendments. If the county seat has not adopted a version of the code, then the 2000 International Residential Code (IRC) and the 1999 National Electrical Code (NEC) apply.

The county seat for Harris County is Houston, Texas. Therefore, the unincorporated area of Harris County uses the following:

The current Houston Building Code [which is called "Houston Amendments to the 2006 International Building Code, effective December 31, 2010"].