I’m wondering if anyone else is struggling with mobile food vendors.
A food truck can certainly generate a lot of wastewater. Then you’ve got all that fat and grease. We consider anything like that being poured into a catch basin being classified as a spill. You can’t catch everyone or put up CCTV on every single one, so that often means doing regular inspections of each basin, but with an emphasis on the ones that are closest to where the food trucks tend to operate.
Then you need to have updated bylaws that can help you come down hard when you do catch someone.
There are also some good inserts and spill response kits that can help you limit the damage when someone does get sneaky and put their wastewater into a catch basin. We use these folks for our needs in this area: http://www.spillsupply.com/Stormwater.html