I've been using this stovetop espresso maker for a few years, unfortunately...The water chamber appear to be coated with some teflon-like substance when I first purchased it, and soon became discolored in a multi-colored metallic way....I called espressozone.com who i had bought it from, and they said it was normal...packaging states that it's all stainless steel, but it isn't, for sure....I use filtered PUR water only, so it's not a water issue....I really dismissed it could be the cause of some of my health issues because it seemed so minor...but then I came across other review today that corroborate what I've thought all along...it's not normal and could cause health problems. I'm officially recycling it and getting a different one. I do use it 1-2 times a day, and yes it has some corrosion in the water chamber that is unexplainable, given that stainless steel is not supposed to be able to rust or corrode...I'd avoid this entire company's product line if I were you.