Your pressure tank lies within your well pump and the rest of your homes plumbing. Its generally less than half the size of your hot water heater. It’s purpose is to act as a pressure switch to your well pump. The tank fills with water pushing the trapped air to the top of the tank. When the air pressure drops below a pre-set amount, usually 30-40 psi, it turns on the pump. When the pressure gets within the target range, usually 50-60 psi, the pump is turned off.

When the tank loses too much air it becomes “water-logged”, and that causes the well pump to turn on and off again fairly frequently, and you’ll notice a marked loss in water pressure.

How to fix a waterlogged pressure tank:
1. Turn off potential to the pump
2. Attach a garden hose to the drain valve located on the bottom of the tank, open the valve and drain the tank of all pressure
3. Now turn on a faucet to allow all the water to drain from the tank
4. Turn off the faucet, close the drain valve, remove the hose, and turn the pump back on.

Usually a tank becomes waterlogged due to a leak. examine your tank for any spots of corrosion. Tank plugs are available, but its a temporary solution and should only be used as a stop-gap until you can replace the tank.

If, when you turn on your faucets, you get a blast of air, your pressure tank may be “air-bound.”

How to fix an air-bound pressure tank:
1. Turn off potential to the pump
2. Attach a garden hose to the drain valve located on the bottom of the tank, open the valve and drain the tank of all pressure
3. Replace the air volume control whether your tank has one
4. Close the drain valve, remove the hose, and turn the pump back on.

If the problem persists, you probably have a leak in the piping amoung the well pump and the house, and should signal a licensed well contractor.

Original post by NewB