Which Pageant?
IMSMC there is a pressure switch on the floor in the offside bed locker in the inlet water pipe. There is adjustment on it. Turn the knob slowly (can't remember which way but it won't be much) until the pump stops, turn the taps off, and then back the knob a little. Keep adjusting back and forth until you get to where the pump starts when you turn the tap in and stops a second or two after you have turned it off.
I am quoting from what I can remember of our Pageant Majestic. If yours is a different model, there may be an adjuster on the back of the housing in the caravan wall where the pump is connected. Whichever type adjust VERY slightly each time after you have found the switching point.