Harris County will need a completed residential application and an accurate and detailed site plan. Residential permits apply to any development that occurs on private property and not for commercial use.See the Harris County Appraisal District's (HCAD) form for application requirements. Complete the form and submit it with the required documentation to HCAD. Learn how to apply for and obtain a building permit in Harris County. Here's your complete guide to Harris County, TX permitting. The plan relies heavily on increasing the supply of multifamily and single family housing, calling for the construction of 3 million new housing units. The following depicts the minimum plan submittal requirements for some scopes of work.