Don't use water, since its warmer then whats on your glass. It can and most likely cause it to crack. I was spraying my house off 1 summer. Wasn't that hot outside. Some of the debris got on my car, so I turned the hose onto the car. I heard the windshield crack. It was only about 100* that day.
A couple years ago Napa auto parts got fined I believe $500,000 for accidentally sending -20* washer fluid to California valley area.
This article may have some insight for some of you.
You and the Law: Looking for winter windshield washer fluid? Good luck!
