The person in charge shall ensure that the water system on the mobile food unit:

(1) Is supplied from an approved source of water;

(2) Is designed and constructed in an approved manner;

(3) Is filled from the approved water source through a food-grade hose;

(4) Is refilled as frequently as necessary to furnish enough hot and cold water for handwashing, food preparation, utensil cleaning, sanitizing, and facility cleaning, on the mobile food unit;

(5) Has a water supply tank with a minimum capacity of five gallons for handwashing;

(6) Stores liquid waste in a wastewater retention tank with at least fifteen percent more capacity than the water supply tank; and

(7) Retains wastewater on the mobile food unit until disposed of by an approved method.