I have a pressure regulator for the water coming into the home. However, when I read the pressure with a gauge it still shows as 135 psi. When water is flowing in the house, the pressure reads 65 psi and is adjustable. I can adjust is down really far to 15 psi and then adjust back up the 65 psi. But I am unable to adjust the "standing" psi of 135 psi (when no water is flowing in the house). Shouldn't that be 65 psi as well? I replaced the parts of the pressure regulator and still the same problem exists. Any thoughts?

The standing pressure should be at sixty five. When you run water it may drop a bit, but not much, if at all. Sounds like you need to replace the complete pressure reducing valve, since you have already changed out the guts.

That regulator is likely a pressure reducing valve PRV. If so it does not have a gauge but one may be mount before or after the gauge. Is your "standing pressure" between the PRV and the water meter o is it after the PRV? Your incoming psi may always be 135 and the PRV drops it to whatever you set it at, 45-50 is about perfect. http://www.watts.com/pages/learnAbout/reducingValves.asp?catId=64

Also... Make sure you have correct pressure regulator. There are several kinds with different pressure reducing capacity. You should have Wilkins Model 600 or 70 ( or similar ). These units reduce pressure to max 75psi. Milo