Bleach is a commonly used disinfectant, and is an acceptable method of sanitizing feed and water buckets. When using bleach, do not use it full strength; dilute it. It can cause you eye or lung irritation. Be sure to dilute it according to the label information and to thoroughly rinse all items. 

Before bleaching buckets and any other items, clean them. It is essential to remove all organic matter. Items with manure, dirt or dried-on feed are not clean and will not be truly disinfected.  And again, be sure you thoroughly rinse any items that you disinfect as well. 

I hope this helps.