Abstract: The present invention discloses a water heater system, comprising: a heating unit capable of heating water; a pump communicated with the heating unit; a gas inlet structure disposed on or communicated with the pump, the pump being capable of mixing a gas and water flowing into it; and a pressure regulating device disposed downstream of the pump. The water heater system provided in the present invention is applicable to scenarios of any existing water heaters, including electric water heaters, gas water heaters, solar water heaters, air-source water heaters, etc., and can produce micro-bubble water for use by the users, which is not only water saving but also environmental protective. Moreover, the micro-bubble water has a strong cleaning performance, and thereby greatly improves the user experiences.