It is not uncommon to pour tap water into your coffee machine and be under the impression that the hot water coming out of it is good for brewing your coffee. When In fact, not using filtered water will affect your coffee's taste and its aroma.
The change in the coffee's taste and aroma is due to the chemicals used to treat drinking water, such as chlorine, a substance that will not be easy to remove even if you boil the water. And it is less likely to be removed by the water heater inside the drip coffee machine.
Now, if your thinking that water is just water and as long as you can drink it's ok. Maybe, I can change your mind.
Not all, but there are some unique specialty coffee beans on the market which have been grown by family farms with nothing but love and delicate care. These coffee beans are then put through various tests until the perfect roast is found for your enjoyment. Therefore if you truly want to enjoy and expose the real flavors in your coffee it won't be a bad idea to filter your water. Plus, filtered water is better for your over all heath.