Hello, I have owned my house for about 10 years. I have always had weak water pressure going to my upstairs bathroom shower. The upstairs sink has no pressure problems. We also have a downstairs bathroom, which has no problems with pressure. We have mostly copper plumbing. There was a few pieces of 3 inch galvenized pipe,but those were clean. The upstairs bathroom is one of the first pipes that come of the water line when it enters the house. It looks like the piping is 3/4. The pipe that goes to our bathroom tappers down to 1/2. any help will be greatly apprieciated..ty
Pressure is the same throughout the plumbing system generally. Reduced flow volume can be misinterpreted as low pressure. If you're confident that the pipes themselves are not restricting the flow volume substantially I'd focus my efforts on the shower valve itself. It could have an obstruction and could need to be replaced (usually not a hard thing to do).
Another thing to try first is to remove the shower head, assuming this shower doesn't have a tub diverter spout. Sometimes the shower head can become clogged up with dislodged minerals from the pipes. Remove the head and see if water will shoot out of the pipe it connects to with any force. If there's a tub diverter that'll accomplish the same thing...Low volume there?...Look at the valve.