Water is indispensable for living organisms, including humans. On the other hand, despite the abundance of water on Earth, most of it is sea water, and only a small portion of the fresh water on the earth's surface is accessible to us. This small amount of freshwater is actually a form of water circulation process in nature (steam, rain, river, lake, sea water, etc.), and ultimately is linked to all the water on the Earth. People consume water from the natural environment in their daily lives and industrial activities, and finally return to the natural environment. In order to optimize the circulation (Life cycle of water) of water, HORIBA contributes to the use of measurement technologies.