A malfunctioning water pressure regulator will cause a change in the pressure of water when you turn on the faucet. Fluctuations in water pressure usually means you have a bad regulator. The location of a water pressure regulator is commonly on the outside of your home on the line leading into the basement or wherever your water pipes are located. When a regulator goes bad there may be so much pressure that damage occurs to the faucets and lines. The pressure can also go so low that the when a faucet is turned on there is no flow or water just drips.
Turn the water faucet on in the room farthest from the where the water comes into the house from outside. Watch the flow of water and determine if the pressure is too high or too low.
Find the gauge that tells how much water pressure is going onto you water lines in the basement from the water main. The water regulator is located on the outside of the house where the pipes bring water into the basement of your home. The reading on the regulator measures PSI (pounds per square inch). It is a round dial with a white face and a needle that points to how many PSI are flowing in the pipes.
Read the gauge. If the reading is 80 or highter then the water pressure is too high for your waterlines and fixtures inside the house. A 40 PSI or less reading says there isn't enough water pressure coming into the house from the water main.
Remove the water pressure regulator and replace if necessary. You can use a plumbing wrench to loosen the regulator and then install the new on and tighten it back up with a wrench. Any home owner can replace a water regulator if he has enough strength to turn a wrench.