There are three different ways to easily adjust the water pressure.First, use the Comfort Pressure Dial by turning it slowly to the right (starting at the OFF position).Second, turn the Water Diverter Valve Handle to increase or decrease the water pressure to the ToothShower. The more water flow diverted to the ToothShower, the stronger the it’s flow to the accessory tips. The Gum Massager works at its optimal capability with all water diverted to the ToothShower.Third, some showers can have the water pressure increased or decreased at the shower faucet/knob by pulling or pushing on the knob. It is recommended to start on the lowest water pressure until your gums are comfortable with water flossing.