The long water lines have been replaced under the house, but not the lines in the wall. What would the cost be for kitchen, 1 full and one 3/4 bath?

I recently moved into a house that has been unoccupied for over a year. The water in the fridge door tastes funny. Is there a way to flush out the lines?

You can barely see them but they leave black streaks when you dry the tub. Sometimes you can see a puff of Grey water comes out when you are running the Hot Water only. I mainly notice them in the soaking tub that does not have an aerator or screen.

I have a shower that is upstairs and there is little to no hot water pressure and the cld is slowing up over time... I am sure that there is calcium or lime in the line. My question is how do I flush so I can once again take a shower because as it stands there is not enough pressure to force the...

Is it necessary to flush new supply lines for shower installations? How is this done? What is a flushing port? Thanks