Not for the squeamish! Jim from EZtankless shows us why our hot (and cold) water may not be as clean as we think. All tankless water heaters need filters and/or softeners to operate correctly for the long term. Tankless heaters do not have the capacity to hold mineral and debris deposits. Regardless of what brand you buy, if the water is not filtered, your heater will eventually prematurely malfunction. http://www.eztankless.com/