We receive our water from a spring fed well. There is approximately 125 feet of pipe from house to spring house. We have obvious air in our line. We have replaced 2 check valves and foot valve as well as checked for obvious leaks in house. The pump does not run continuously. Pressure is maintained in our pressure tank. Water sprays from the faucet when turned on and pipes rattle loudly when toilet is flushed. How do we find leak without digging up 125 feet of pipe.
Assuming you have a shallow well pump. I would start looking from the pump to your well. This is where you will get air sucked into the water without having a water leak. Tighten all the hose clamps, you may need to add thread sealant to primer plug or any threaded fittings.
I had the same problem last summer and at first thought it was the neighbours line, we checked it out but found no problems with his lines so we searched my house finding no problems, so we blocked each end of the line and pumped 60psi of air into 240ft of 1" water line and walk from house to spring several times with no luck of hearing air coming from ground so decided to reconnect, just after that we primped my pump and was receiving water with air again, this went on for 2 days then as i walked back down to the spring I stepped on a spungy peice of ground, jumped into the small backhoe took two scoops and water and air filled spatted everywhere but what a blessing