Well pump

Hi, my well pump motor recycles every 25 minutes. The pressure will drop down to 20 pounds (it drops at a rate of 1 pound per minute ) and then turn on it will raise to 40 pounds and then shut off what could be the cause? How do I do a test to know absolutely positive that it's in the house or outside of the house? A foot valve or a cracked line? The pump has two lines on the front of the pump going to the well.

Thanks

Assuming there is a shutoff valve after the tank and that it is in good working order, shut it off. If you still lose pressure the leak is not in the house.