Why You Should Use Distilled Water in a Poultice

Distilled water should be used in poultices, because it does not contain minerals such as chlorine, iron, and others or contaminants that can reduce the effectiveness of the poultice. Poultices work by drawing staining agents out of a surface and into the poultice material. 

Why should you avoid using tap water? There are a couple of reasons. First, bacteria or other microorganisms can sometimes be found in non-distilled water sources, and this is an important consideration if you are using a poultice to treat surfaces used for food preparation or in medical facilities. Distilled water is pure. Second, if you use tap water in a poultice, and your tap water contains iron, the area where the poultice is placed can turn yellow.