One eye waters or teers all day ?

Watery eye: Do you wear contact lenses? Have you gotten a foreign body (piece of dirt/plant/etc in your eye that may have scratched it? Is there pain in the eye? Is it red & swollen? Any pus? Do you use mascara? When did you last change it? (should change every 3 months at least). If any of above are true, see your eye doc for evaluation & treatment.

Tearing : If the tearing is only in one eye and runs all day long, it could be due to a tear drainage system blockage. See an eye doctor.