I recently replaced my hot water heater, basically same capacity, etc. as the previous heater. I am noticing a drop in water pressure in the entire house, guess would be 20-25%. The only change is I used a dielectric union between the new heater and copper pipe.

I have to assume the water heater replacement created the drop in pressure. Is there any way to test if I may have created a constriction in either the hot or cold lines? I assume a constriction would reduce water pressure -- it is consistent throughout the house: kitchen and bathrooms.

Thanks... Tom.