Is it necessary to use distilled water while dying hair with henna?

Im going to use a natural henna/indigo mix to dye my hair, but the instructions say to use distilled water (distilled being in bold font) because any minerals could change the color. Do i really need to go out and buy distilled water? or is there any way to distill water yourself (without actually collecting water vapor and everything). I have a Brita water filter; would that take out the same minerals as distillation?