Potable water is water that can be consumed. Also known as drinking water, it can also mean the water has been treated in order to be safe. The safety of water is tested to look for harmful contaminants. The issue of access to potable water during construction is important. It determines the septic system installed. Because water quality is so important, filters may be required in certain locations to remove heavy contaminants or particulates that could make the residents of a household sick.