The right water is crucial to the taste of the coffee because coffee is comprised of 98% water.
Knowing the hardness of the water you use in your espresso machine is very important. Not only can using hard water affect the taste of coffee but it can also damage machine components. Hard water produces scale on machine parts which requires machines to be descaled with greater frequency to keep it running optimally.
You can test your water hardness using these water hardness testing strips so you can be sure you are descaling accordingly.