Thanks for the clarification of the system Cecil.
If your pump already has a electric contactor a smaller size relay could control it. If your pump is turned on with a manual contactor or a big knife switch then as has been said, a contactor switch with adequate rating (probably a NEMA 1 contactor) would be needed to keep from burning out a switch not designed to handle the load. Often the switch on any float mechanism is a relatively low power device and it controls a larger switch that actually turns the large load (your pump)on and off.
One comment about your pressure tanks for your house and the pump kicking on and off often. We used a well pump and pressure tank for probably the first 40 years of my life. If those pressure tanks get "waterlogged" the pump will kick on every time you open a faucet. Easy to tell if you have a pressure gage on the system. If when a faucet is opened the pressure drops rapidly, the tanks are full of water and do not have the proper air gap in the top of them to maintain pressure till the tank drops about half the gallonage of the tank.
Just something to check.
