Pulsing when faucets turned on in new house

I just bought a 2 year old house with an 80 gal. A.O.Smith elec. hot water tank. The hot water tank has a Thermal Expansion Tank plumbed in above the water heater.

All faucets in the house exhibit a slight (but rapid) pulsing of the water when they are opened. Normally I would expect the water to flow smoothly but in this house the water flows with a minor amount of pulsation the entire time the faucet is turned on. This is more noticeable when the faucet is sightly on rather than when it is fully opened - however, it does pulse all the time - just more noticeable during a lower flow of the water.

Any ideas what the cause of this is? I am on city water (Charleston SC).

Thanks in advance
Robert

I would suspect a check valve or pressure regulator valve where the house is connected to the city system.