That unit has a lot of stuff you don't need...
If you're filling a bucket or tank, you don't need the pressurized storage tank. You also don't need the counter top dispenser. Both of those items are for permanent drinking water installations, and 20gal per day is very small.
For a very basic system that will fill a bucket or tank, this is all you really need:
http://cgi.ebay.com/New-Portable-4st...QQcmdZViewItem
For a self filling system, I suggest stepping up to a system that has an automatic shut-off valve like this system, plus add an optional float valve. Get yourself a large plastic tank, install the float valve, and the system will automatically stop when the tank is full:
http://cgi.ebay.com/AQUARIUM-2-110GP...QQcmdZViewItem
Then you can add plumbing out from the bottom of the tank and use gravity to fill you rinse tanks. I use 1" PVC and a ball valve... the water rushes out so fast, it fills a 12gal tank in seconds.