Although the method of use differs from school to school and depending on the type of service, the suichu fulfills various roles throughout the service, being used for adding water to the tea kettle and to the bofura (water pot), for pouring water into the tea bowl, teapot, and yuzamashi (water cooling jar) at the start of the ceremony to wash and purify them, and to cool the tea bowl and teapot in the heat of the summer.
流派や手前によって異同があるが、やかん、ボーフラに水を足す、手前の最初の方で、茶碗、急須、湯冷ましを清めるために水を注ぐ、夏場は茶碗、急須を冷やすための水を注ぐ、など、手前の中で大きな役割を果たしている。