To increase water pressure in a pump, find the pressure switch with a gray plastic cover over it. Remove the cover by unscrewing the small nut on top of the cover with plumber's pliers. Find the 1/2-inch nut on the pressure switch, and use a 1/2-inch wrench to turn the nut clockwise. This nut controls the pressure for cut-in and cut-off pressure.
Watch the pressure gauge as you turn the nut. It first drops completely and then rises, causing the pump to turn off. Keep turning the nut until the gauge reaches the desired pressure. The second nut on the pressure switch is 7/16 inches; adjusting it changes the pressure gap for the on or off cycles. Turning this nut clockwise increases the cut-off pressure, while counterclockwise lowers the pressure. As you turn this nut, watch the gauge to ensure the pressure stays in a safe range, which is at least 20 pounds per square inch.
Once the adjustments are completed, replace the pressure switch cover. It takes at least four or five pump cycles before the adjustment is reflected in the water flow. Be cautious when handling the water pump, because you have to leave the power on to read the gauge.