I apologise for the late reply. I was on holiday and had to take a look at the kettle first. Yes, the inside of the housing is completely made of stainless steel. It also has a black plastic part at the top of the spout and the handle. There are two small round plastic discs where the water level indicator starts and ends on the outside. I clean the kettle every week with vinegar - no problem. Furthermore, we are totally satisfied with this product and would choose it again.