Hard water is easy enough to deal with. Just use a Britta filter, I live in London and our water is very hard. I've only had to descale my kettle once in the last 4 years since I bought it, which was a mystery until I realized my girlfriend was making tea using tap water.
My kettle is just a 0-100 kind, so in order to do 80-85C for my morning coffee, I use my meat thermometer with the alarm set on 76C. By the time I flick the kettle off and the energy finishes dissipating into the water, it'll be ~82C. YMMV