A good first step to determine which is more stringent is to review your local code to be sure it contains at minimum the general categories contained in the CGP. If not, you’ll know that you need to follow the CGP. If so, you’ll need to review your local code in detail to be sure that all of the requirements are included. The general categories are as follows: 

allowable stormwater discharges
allowable non-stormwater discharges
limitations on coverage
a stormwater pollution prevention plan
releases in excess of reportable quantities
treatment of spills.