Just so you know I spent the last 30 minutes reading all pressure related questions but I still need to post this. We have a drilled well and Culligan Water Softening system. Lately I have noticed water pressure steadily dropping and then recovering minutes later. Especially noticeable while watering the lawn. Gets so low the sprinkler won't even cycle. I checked the pressure gauge on the pipe next to the pressure tank and it reads between 40-60. I checked the air valve and it had no water. I checked the contacts on the pump control and they look great. The system is only 7 years old or so.

Something has changed because it was never like this. We have a 650 foot deep bedrock well with relatively low yield and very hard water.

Am I looking at a new pump? Help!

Am I looking at a new pump? If the gage holds 40 to 60 PSI and suddenly drops until the pump picks it back then one of two things come to mind.
1) a check/foot valve that's operating intermittently or,2) a leak on the pressure side of the system. If you have zones try shutting them down one by one. However, My bet's on the check valve. Good luck, Tom

Free, I may have misread your post, but it sounds like the pressure gauge is not indicating a drop below 40#. Is that the case, so that when the pressure seems low, your gauge is still reading at least 40#?

Where is the check valve? Is this something I can isolate and diagnose? As far as the pressure goes it seems to be kicking on at 32 and off at 58. I see you can adjust the two nuts to change the settings but it seems kind of inexact. Is there a technique?

This site will tell you how to adjust the switch. Look about halfway down.

How to adjust water pump pressure, pump cut-on pressure and pump cut-off pressure - private pump and well system do-it-yourself repairs (http://www.inspect-ny.com/water/WaterPumpAdjust.htm)

32# cutin is not unusual, but it might be too low for your sprinkler system. You can try adjusting the cut in pressure up (large nut), but you might then have to use the small nut to take the cut off pressure down a little. I wouldn't push that much over 60#. With a 26# differential between cut in and cut off pressures, you are going to notice some difference in pressure as pressure goes up to 58 and then down to 32.

The checkvalve, for you, might be in the well, just above the submersible pump, or it might be above ground. At any rate, it will be between the tank and the pump. It will normally cause the system to cut on/off when no water is being used. This site will show you pictures of checkvalves.

Water system check valve location & purpose - private pump and well system do-it-yourself repairs (http://www.inspect-ny.com/water/CheckValves.htm)

As far as the pressure goes it seems to be kicking on at 32 and off at 58. I see you can adjust the two nuts to change the settings but it seems kind of inexact. Is there a technique?
If you wish to reset your control box, here's how to do it.
First turnoff the power at the breaker box, then pull the cover off the pressure switch and you will see two spring loaded bolts secured with nylon nuts. One tall, one short. To increase the cut in pressure, turn the nut on the tall bolt down. To increase the cut out pressure,(that's the one that will give you more pressure) turn the nut on the short bolt down. Good luck, Tom