I live in Cranston, R I. I had pinkish orange residue on my shower head and build up around my bathroom sink with a water heater that I have since replaced because it finally burst. The plumber told me that the pinkish residue shows up before a water heater is ready to burst as it is the metalic sludge such as iron rust that builds up in the water heater over the years. I did not have MAC before I moved to this condo.