resident water pressure(single home)

I am not a plumber, I just tested my water pressure at the main entrance
outside of the carage, and it shows 110psi. From researching on this, 110psi is way too high. But I'm still not sure, This is with everything shut off, but when I turn on one of the water fixture in the house, the water pressure went down to 65psi. Do I need to ajust that 110psi to come down with everything shut down???? or am I o.k. How do I do that.

Thanks
TnT

At 2-3 AM it will probably be be much higher. Anything over 65-70 psi is too high, so get a pressure regulator or keep enough water running 24/7 to keep 65 psi max..

If you've been reading here you already know this, buy an expansion tank at the same time and install that as well.

pressure

That large a difference usually indicates you already have a pressure reducing valve, but it is defective and needs replacing.