I have low water pressure throughout the house. I

SOURCE: when adding air to a pressure water pump ,i

Sounds like the bladder is gone or inproper air pressure in water storage tank.

Bladder goes bad check it out with step 1
1-
One way to check for sure with everything hooked up. The air valve on top of the tank if pressed you will get water out of the valve which should be only air. This will let you know it should replaced.

If Tank bladder is low in air and not water coming out.

2-If it checks ok put an air gauge to tank to check the air pressure, with a standard 40 gal tank you will have 28 psi of air in tank for it to function properly.

SOURCE: How do I increase the water pressure in my house?

Hi,

Here is a tip that will explain how to adjust that pressure switch, there also are other tips attached to the bottom of this one that will answer other questions also...Water wells and water pumps are great but do take some maintenance...

Well Pressure Switch Adjustment Water Well Problems
heatman101