AquaTru is designed to filter municipal water. AquaTru is not intended for use with any water that is microbiologically unsafe. If you are 100% confident that your well water is free from biological contaminants, you can use AquaTru to purify your water. While AquaTru has been tested to remove cysts, which includes Cryptosporidium, Entamoeba Histolyca, and Giardia lamblia, it is not recommended for water that bay be microbiologically unsafe, such as lake water or other kinds of untreated water. AquaTru has not been certified for this purpose.