Those liquids can be water, soda, wine, urine, feces, or just about anything that is a liquid and not flammable. Most shop vacuums will need to be adjusted for use with water. The reason for this is that sucking up dry objects is very different than sucking up wet objects. The dry stuff needs a filter and also to make your life easier you need to use a bag. If you want to use a shop vacuum to clean your pond we answer that at the bottom.