Abstract: A method of providing a dispense purified water stream from a water purification apparatus involving passing a water inlet stream through a first water purification station to provide a first internal purified water stream, passing the first internal purified water stream to an internal reservoir, and providing a second internal purified water stream from the reservoir, passing the second internal purified water stream into a recirculation loop, measuring the conductivity of the second internal purified water stream; passing the second internal purified water stream to a second water purification station to provide a third internal purified water stream passing the recirculated water return stream into the internal reservoir; calculating the purity of the first internal purified water stream using the measurement of the conductivity of the second internal purified water stream.

Abstract: A water purification apparatus including a first water purification station for a first internal purified water stream. A valve selects either a first dispense purified water stream or a first continuing water stream or both. An internal reservoir receives the first continuing water stream to hold a volume of second purified water, and provides a second internal purified water stream. A second valve able dispenses the second dispense purified water stream. A second water purification station receives the second internal purified water and provides a third internal purified water stream. A third valve selects from the third internal purified water stream either a third dispense purified water stream, or a third continuing water stream, or both. A recirculation loop returns the third continuing water stream into the internal reservoir. A pump pumps the second internal purified water stream from the internal reservoir around the recirculation loop.