I've drained the tank several times over the past 3 years. The last time I did it, everything seemed fine with pressure and everything. Starting about a week ago, I've noticed a steep decline in pressure. It will have good pressure for about 2-5 seconds then drop considerably down to a trickle. When you flush the toilet, it almost stops completely. What can be causing this?

I am assuming you are draining the tank in order to recharge it with air. Sounds like the tank is waterlogged (very little air in tank). That could account for the rapid pressure drop.

It could also be due to an obstruction somewhere between the tank and the house. Once you get the initial surge of pressure, the volume drops off. Do you have a filter, softener, or cut-off valve anywhere in the line? When the pressure drops off in the house, what does your pressure gauge read at the pressure tank? Does it drop down to nearly nothing, or stay up?

Do you have a pressure tank (galvanized) or a blue bladder tank? Answer jisenbes questions and we'll go from there. When the pump shuts off does the gage drop back to zero? Let's hear back with those answers, Good luck, Tom

The gauge stays up and I have a pressure tank. I put a filter inline 3years ago and change the filter once a month. The tank has been there since before I bought the house over 3 years ago. It looks pretty old though. I only say the gauge stays up because I don't hear the motor kick on. I can normally hear it kick on and see the lights flicker a little bit when it does.

If the gauge stays up(eyeball it to be sure), and it is working, then I'd look for an obstruction somewhere. The filter is the first place to start. Most of them have a bypass valve. Turn that and see if your problem goes away.

I changed the filter and drained the tank again and that seems to have worked for right now. Thank you for all the advice.

JM, this tank that you are draining, is the outside galvanized or is it painted?

Galvanized

Then that would make sense. You might want to consider replacing it with a bladder tank. That would eliminate having to recharge it with air.