when water pressure is low, there can be a couple of reasons why:
If water pressure is low, it can be a sign of a leak. To know for sure, you may check your meter for a leak indication. If the silver wheel on the meter is spinning and there is no water running in the home...this will indicate a leak.
Sometimes this can also indicate that your line is in need of a pressure regulator or that an existing pressure regulator is beginning to malfunction. A pressure regulator controls the amount of pressure coming into your home, high and low. Recommended psi is between 45-60.