When I lived with my mum, the water was so hard that we used a tea strainer when we poured our water from the kettle. I kid you not.
Most modern kettles seem to have a filter in the spout — at least the jug types.
But is it really that difficult or expensive to procure a tea strainer?
* I had a great aunt who would make a mug of tea (one of those old-fashioned tall, waisted mugs) by putting in a teaspoon of tea, followed by hot water, followed by milk. Having drunk this she would add another spoon of tea on top of the first, add water, milk, and drink. This she repeated until the mug was half full of tea leaves, at which point she would empty it and start afresh.