In Texas, if your business is required to obtain permit coverage, you must submit an application to the TCEQ that includes a Storm Water Pollution Prevention Plan (SWPPP). The plan must include site-specific protocols, training, facility inspections, and water sampling schedules that will help you reduce and mitigate your business' storm water runoff.
You'll find a copy of the MSGP describing all the TPDES requirements including the SWPPP on the TCEQ website.
A well-developed SWPPP requires detailed site maps that include scale, elevations, water flow, retention pond capacity and other parameters. While it is possible for businesses to develop their SWPPP in-house, it is not a simple task. You may be better off bringing in an environmental specialist to develop all or part of the plan for you.
The TCEQ provides an industrial pollution plan guide as an example on their Assistance Tools for Industrial Stormwater General Permit page, but bear in mind it is only a template and does not guarantee approval.