Question
Situation: I have a new 1 HP irrigation pump with pressurized tank, pressure gauge and pressure switch hooked up to an old well that is 38' deep with 16' of water.  It is 20' to top of water. I am having a problem getting any pressure to build up, it's only getting to about 17. I am using 1.5" pipe down well. If I reduce to 1.25" will I gain any pressure? Any other suggestons to increase pressure? Not even enough pressure to fill pressure tank.

Answer
Could be a couple of things.  I hope that the pump is not pumping water faster than the well can recover.  That would mean that you either need a smaller pump, lower your well pipe or need work on your well.  The other problem would be either an obstruction in the well line, or a defective foot valve.  You would have to pull the well line to determine if either of these is the problem.