Water pressure depends on its connection to the city or well, ranges between 45 and 80 psi (pounds per square inch). Anything out of this range not considered normal for the Residential Need.

-Pressures above 80 psi are too high which you should use a regulator to avoid damaging your house pipe.
-Low-pressure causes could be clogged pipes, faucets, or faulty regulators which is better to consult with a licensed and qualified plumber.