I know Rowenta says to use tap water only. I doubt they ever took into consideration areas with extremely hard water. I was constantly having to clean out my one and only Rowenta because of that. I started using half tap and half distilled. Still cleaning and then spitting. I'd had that iron for well over 15 years. I got a new one that has never had any water in it, just use a mist bottle and no drips and spurts.