I want to calculate the volumetric flow rate (SCFM (standard cubic feet per minute) of a pipe knowing the pressure inside the pipe as well as the diameter of the pipe. I know

Where v is velocity and A cross sectional area.

However, I need help finding out my velocity from my known pressure. I also know that water is the media that is being used inside the pipe. Can I relate the velocity back to the pressure via density? Any help please.

But it sounds like you don't have enough information to solve the problem. You'll need to know the pressure at two locations in the pipe in order to calculate the velocity.