Drain all water still in the reservoir through the cold water faucet.
Fill the dispenser reservoir with clean tap water (about one gallon). Dissolve one teaspoon of household bleach in one cup of tap water. Add this mixture to the tap water already in the reservoir. (There should never be more than one teaspoon of bleach per gallon of tap water.)
Using a clean brush, scrub the inside of the reservoir. Let stand for five minutes.
Drain this water through the cold water faucet only. Wipe the reservoir dry. (On coolers equipped with hot tanks, hold red handle open until chlorinated water flows out. Remove drain plug from back of unit to drain sanitizing solution. Flush with one gallon of fresh water. Replace drain plug. Hold red handle open until water flows from faucet.)
Rinse reservoir by filling with clean tap water. Drain through the cold water faucet.
If your cooler has two faucets, refill the reservoir with clean tap water. Drain through the second faucet.
Place a new bottle on your dispenser. Plug in and enjoy the unit!