Cleaning a water dispenser

It has occurred to me that I am probably hosting squadrons of bacteria inside my water machine which has, to my knowledge, never been cleaned apart from an occasional wipe-down of the taps. I don't have a service agreement with any suppliers as I just get 19-litre bottles delivered by Wellcome and, being a Cheap Charlie, I don't want to pay an (apparently) astronomical sum to have someone come to my house to clean it when I can probably do it myself if I know how. So, my question is: does anyone drain and clean their machine and, if so, please would you give me some tips on the best way to do it? Any advice would be much appreciated, thanks!

how about filling an old water bottle with warm water and bleach, and let the tap run til bottle's empty? then do the same thing with warm water to rinse?

Oddly enough, I was wondering the same thing recently, and I found the below useful...


http://www.wikihow.com/Clean-a-Water-Dispenser


Here is what it says:


How to Clean a Water Dispenser

If you have a water cooler/dispenser, you'll want to clean it regularly. Here's how to do it right.


Steps

Clean your water cooler every 6 weeks, or with every bottle change.


Prepare a bleach solution by adding 1 tablespoon of bleach to every 1 gallon of water that you use.


Unplug the water cooler from the wall and take off the empty bottle.


Use a sponge to clean the inner surface of the water cooler with the bleach solution. Let it stand for no more than 5 minutes, then drain the bleach solution through the tap and into a bucket.


Rinse out the bleach solution by filling the inner reservoir with water four times and washing it out through the tap and into a bucket.


Lift off the drip tray and wash well in the bleach solution. Then rinse in tap water and replace onto the cooler.


Wash your hands with soap and warm water, then wipe the top and neck of the new bottle.


Remove the cap from the new bottle.


Put the new bottle on the water dispenser.

Many thanks! Will give it a go after the New Year excesses...