That is a common symptom of a water logged pressure tank, broken blader tank, or misadjusted pressure in the blader tank or misadjusted pressure switch.

You need a pressure guage connected someplace near the pressure switch.

Watch the pressure as you are drawing water. If it is one of the above problems then you will see the pressure slow drop, but them suddenly drop some more just before the pressure switch closes.

Thank you so much for your reply. It sounds like an expensive problem. I bought the house 16 months ago. Is the water pressure problem something I can check myself or should I contact a pump company?

Unless the pressure tank needs replacing then the costs will be minimal.

You can get a pressure guage at most home horror stores. They will be my the pump. IIRC they are less than $10. You want a 0-100 psi model.

You will need a few plumbing parts to plumb it in. That might be easy or hard depending on the type of pipes that you have and how they are arranged.

Connect the pressure guage and watch it and see if you have the pressure drop like I described.

Here is a link about checking a bladder tank and how to set the pressure.

http://en.allexperts.com/q/Plumbing-Home-1735/well-water-pump-bladder-1.htm

Here are more resources.

http://www.inspect-ny.com/water/watertank.htm

http://www.hammerzone.com/archives/plumbing/well/pressure_tank/replace.htm

http://www.aquascience.net/tanks.htm

This is normal. A pump does not maintain a constant pressure like city water. It pumps up to a certain pressure and shuts off and waits for the pressure to drop before restarting. That differential is usually about 20 PSI. So it is normal for the pressure to vary up and down 20 psi while running.

Thank you for all the great information. I hope to find the root of the problem now if there is one. I will give you an update once I test the system out.

Just wanted to give you all an update. Turns out the solution was to add air to the tank.

The articles were very helpful. In addition to solving my problem, my father's house had such low water pressure, water trickled out of the showers. No one knew and therefore added air to the well holding tank for over 20 years -- the rusted gauge showed the tank pressure under 10. I used my bicycle pump and added air to 50. The pump switch is working as it should. The water is running great now throughout the house.

Thanks again.