My water tank is about 15 years old, the problem I'm have is that sometimes the tank will lose water and run until the tank pressure builts up and I have water again. After that it OK for a while. Also I can not water the lawn or use a water hose without the pump runnig the whole time?

my water tank is about 15 years old, the problem im have is that sometimes the tank will lose water and run until the tank pressure builts up and and i have water again. after that it ok for a while. also i can not water the lawn or use a water hose without the pump runnig the whole time?
The first thing I would suspect is the check or foot valve. Sounds like it's letting pressure bleed out of your system. Check valves, (see image) are usually located on the suction line near the pump. Foot valves are located at the well point, however, if the foot valve is faulty and allowing the loss of pressure you can binstall a check valve on the suction line with out having to pull the wellpoint and replace the foot valve. Good luck, Tom