Measuring the pressure in copper pipe plumbing is relatively easy to do. Here are a few steps that can help guide you.
Step 1 - Find Water Surface Elevation
To do this, you can just find the nearest water tower to your home and add the height of the tower to the elevation of the water surface. Write this number down. If you want to do it to the nearest lake or other body of water, you can do that too.
Step 2 - Find Pipe Elevation
Now, find the elevation of the pipe. If pipe is above ground, then take the distance between the pipe and ground. If it is below, do the same. Write this number down.
Step 3 - Calculate
Now, take the water surface number and subtract the pipe number from it. Then, if you are measuring in feet, this will be your feet head. To find the pounds per square inch, which is generally the number you want, multiply the number you got by 0.433. if you were measuring in meters, then it would be the meter head, and you multiply your number by 1.42024 instead.
These 3 steps should help you to find the water pressure that is flowing through your copper pipe plumbing.