Measurement system for use in desalination system, desalination system, and desalination method

A desalination system is equipped with: a water tank (102); a water-repellent particle layer (104A) arranged beneath the water tank and composed of water-repellent particles; and a liquefaction layer (105) arranged beneath the water-repellent particle layer. The system is so adapted as to produce fresh water from a liquid in such a manner that the liquid is placed in the water tank, the liquid is heated to generate water vapor, and the water vapor is allowed to pass through the water-repellent particle layer and is liquefied in the liquefaction layer. The water-repellent particle layer comprises: a first particle layer (1041); and a second particle layer (1042) composed of second particles that can be distinguished from first particles in the first particle layer. The desalination system is provided: a particle measurement unit (201) for measuring the amount of the second particles located in the liquid; a determination unit (202) for determining whether or not the amount of the second particles measured is equal to or more than a predetermined value; and a control unit (203) for giving a warning, or halting the placement of the liquid into the water tank or decreasing the speed of the placement when the determination unit determines that the amount of the second particles is equal to or more than the predetermined value.