If there is a WalMart close to you, there will be a product on their shelves that will take care of that problem.
such as this:
http://www.walmart.com/ip/Camco-Drinking-Water-Freshener/14504326other stores with camping related products will have similar products and is safer than pouring in household bleach.
in essence, you need to rechlorinate the water to kill bacteria, algae etc that are growing in the tanks/lines and causing the smell
2004.5 2500HD CCSB Duramax/Allison - was an Overheater fixed it!!! Bilsteins, Banks stuff, Hellwig Sway bars front and back
2010 Crossroads Cruiser 30QBX
2 Doberman/Rhodesian Ridgeback Crosses - brothers
2 Beagles
1 Shih Poo
1 Shih Tzu
1 Camping Cat
1 wife