No, since a bulk bag's fabric is made from a woven material, the bag is not "water proof". Users usually want a coating or lamination as a moisture barrier, by moisture barrier we mean a light amount of condensation or light amount of water. Lamination is simply a moisture barrier, however the use of an internal poly liner works best in many typical applications, technically it still is not 100% water proof. The difference between using a coating/lamination or using a liner is in the amount of moisture that you are trying to keep out of the product, and how much you want to assure that this does not occur. Standard bulk bags are not water proof, and are not typically designed to carry wet products, however there are other type products in the market designed to hold liquid, i.e. liquid liners.