At What Point Does the 2015 International Plumbing Code Dictate

At what point does the 2015 International Plumbing Code dictate that a nonpotable water system be designed by a registered design professional or person authorized by local jurisdiction?

A) discharge of more than 250 gallons per day
B) discharge of more than 360 gallons per day
C) discharge of more than 100 gallons per day
D) discharge of more than 150 gallons per day