Potable means “safe to drink.” If water used for eyewash and showers is from a municipality, then it meets the definition of flushing fluid per the ANSI standard because it’s treated and tested to meet Environmental Protection Agency (EPA) drinking water standards. If, however, well water is used it’s suitability must be confirmed via adequate testing to ensure it meets the same EPA requirements and can thus be used for emergency eyewashes and showers.