THanks guys i found some stuff in Rv parts. the manufactuer is a mystery ill have to wing it

I’m a newb to street vending, but have spent 20 years in restautrant kitchens. I recently bought a cart that needs a little TLC. I need to replace the grey water holding tank, and also repair the potable water tank. the former owner let the pipes freeze, and for some reason cut the fill port on the H2O tank off. Most of my parts issues are plumbing right now. If any of you know some good web sites please help me out, i have looked at every restaurant supply i could find with very little luck. ill try to attach a pic of my baby