Several things can cause low water pressure. One problem could be the amount of water your local utility company is pumping out. Another is the age of your pipes and the amount of rust in them. Blockages and other restrictions in your pipes can also lower water pressure. Other considerations are: a partially closed or malfunctioning shut off valve, crimped water line, a failed or missing pressure regulator, plugged filters and malfunctioning water softeners. If you are experiencing problems with low water pressure, contact a plumber.