Fluid water is a suitable interface to use in performing flowing sound and music, since fluid and sound have common characteristics. For example, both media change shape over time and so they cannot be grasped. We use flowing water in a musical instrument installation. As water is frequently used in daily life as an essential resource among various fluid materials, such an instrument using water will be more friendly and become an amenity in our life. Recently there have been many installations and interactive artworks using water, but they do not exploit the ability to use water itself as a medium. This research aims to find practical uses of fluid media for musical instruments. In addition, we propose a method to sense the amount of water flow for enjoying music. For judgement of user's actions, we use the changes of the upper flow from the faucet and in the lower flow toward drains as well as the difference between these two values. This conflgulation leads to a novel concept of "Source and Drains," which is also applicable to traditional wind instruments. Based on this concept, we introduce installations that are named "Tangible Sound" #1 and #2 as novel musical instruments that use water as input media.