The house was built in 1955 - not quite sure about the pipe material.
My house was built the same year. I can tell you what's happening but you're not going to like the solution. We have galvanized iron water pipes that have built up rust over the years. The water sits in your pipes collecting iron oxide and other minerals, ( sulfur. Calcium carbonate,ect) When you make a draw the minerals will flush out after you run the water and it's clear. The solution would be to repipe the house in plastic. And I'll bet that when you take a shower and someone flushes the toilet the cold water drops to nothing. OUCH! PS. I repiped my house last year. Good luck, Tom