JW is right that you don’t need a CSV for a 5 GPM pump that just fills a cistern. But a CSV would be a beneficial addition to the booster pump/pressure tank system that supplies the house.
Years ago we never installed check valves on irrigation pumps around here in the cotton fields. That way the pipe would drain back and nothing would freeze over the winter. These pump where started maybe three times a year, and then left running for months at a time. So we didn’t think check valves were important. When you shut off the power to a 5HP or a 30HP, they would really spin back fast. Over the years we realized this was hard on the motor thrust bearings.
Occasionally a contactor would stick or someone would turn the pump back on before it had stopped spinning backwards. This would nearly always break the pump shaft.
Later we started drilling holes in check valves so the pipe could still drain back, but it wouldn’t flow backwards fast enough to spin the pump/motor. They even make flapper style valves that leak back a certain rate just for these application.
With a low producing well you want a check valve on the pump. Without a check valve some times the well will be pumped dry before the pipe is refilled. At the very least it reduces the amount you can draw from the well each time.
But even with a 5 GPM pump that is only filling a cistern, multiple check valves are still not a good idea. As long as all of them are working perfectly you won’t see a problem. But when there is a small leak back the upper most check is holding a negative pressure in the pipe, just like holding your finger over a straw full of tea. Then on pump start, the bottom section of water hits the upper check valve with tremendous force. Since water hammer like this can cause a shock wave 10 times stronger than the pump can even produce, the bottom sections of pipe may see spikes of hundreds of pounds of pressure. And it can also shatter a thrust bearing.
One check valve on the pump will not cause a negative pressure. Filling the cistern from the top leaves and air gap. That way it can’t drain the cistern down the well if the check valve does break or you get a hole in the pipe.