Where does the water in tears come from and can you become dehydrated from crying enough?

Tears are from eye: You'd have to cry a lot to really dehydrate if you're otherwise in good health. The eye's lacrimal system secretes tears to protect the eye. When we cry, there's an additional stimulus from the emotional centers in the brain that ramp it up. If you're not being held without access to beverages or stranded in the desert, you are likely fine if you cry.