Replaced 3 foot valves and pump keeps running

Hello! I have a 2-line jet pump (In the house) which started running when no water was on and no leaks inside house. I have had the foot valve replaced 3 times in the past 6 months and the problem persists. The pump runs every 9 minutes now/still; it runs normally when water is being used. The well is 80 feet deep with about 40 feet of water, 6" casing, dates to 1969. The pipes inside the well were pressure tested and the pressure dropped a little, but that was before the last foot valve replacement. Any ideas? Thanks!

Have you got a ball valve that can shut off water to the house? That is the only way to make sure you don't have a leaky toilet or something in the house. Cause if the water is not leaking into the house, you have another bad foot valve.

Thanks, Valveman. I turned the water off between the pump/guage and the rest of the house and the pressure drops like a rock. I am certain it's outside. Is there any reason why a new foot valve would start leaking within and hour after being put in? It has happenned twice now in the past few months. My plumber wants to put in a submersible pump to solve the problem ($1600) but I would rather just keep the jet pump and figure out what is wrong. Thanks!

Unless it is just a badly designed foot valve or you are sucking up rocks then no, footvalves should last a long time. If the line to the well is underground, the leak maybe in the small line going back to the well, not the foot valve.

Ok, I'll have the lines pressure tested where they enter the house, and I plan to buy my own foot valve. I guess you can't recommend brands here? Thanks again for your help--I enjoy the forum and have learned more about wells than I ever planned to.