well pump takes a long time to shut off

I've had this house for a year. I've never lived in a house with a well before. The pump usually stays on for a few minutes, but now it stays on for a long time, like maybe an hour before it shuts off. I haven't timed it because I don't want to leave it on for that long because I thought it might be bad for it. During the summer, when I was using it for irrigation, the pressure would drop and I would have to clean the sediment filter I put on it, but I have cleaned the filter, and that's not it. The pressure gauge said 0, so I replaced it. When I turned on the well, it started at 20, then slowly rose to 35 and stayed there until I turned the pump off. The next time it hovered around 20. The third time it slowly when down to 0. Now it stays about 19. The air bladder pressure is about 26, but was checked before the problems started. It is a 2 hp pump.

It's probably not relevant, but after a big storm at the end of January, the water turned brown, and I was told that it is an inadequate casing. Thanks for your help!

-Heather

You don't say whether it is a jet or submersible pump.

If its a jet pump, the jet in the ejector assembly could be worn from the sediment running through it. The pump could be worn or both.

If it's a submersible, the pump could be worn out, there could be a split in the drop pipe, or a rotted/cracked fitting at the pump. There is a chance that you are running the well dry too.