Does windshield washer fluid self evaporate?

[deutsch100]

My 35d is 6.5 months old, 4500 miles. I have NEVER used the washer fluid. My HUD and i-Drive warnings popped up today, that my fluid was low/empty.

Also, our garage floor is very easy to identify if anything is leaking...and the floor is spotless clean. So, at least while parked at home...there is no leaked washer fluid.

Does E70 washer fluid just dry up? Do I need to, or should I buy BMW washer fluid, or is anything from the auto parts store fine?

The dealer said that washer fluid will only be covered/paid for by BMW, if I bring my car in for a scheduled service, via the car's determined mileage/time base service intervals.

Thanks!