My eyes are constantly watering and I'm not sure what's causing them to water?

Possibly dry eye. Tearing can by a symptom of dry eye. The large tear gland (lacrimal gland) can excessively produce tears if the eyes become dry enough (reflex tearing). Allergy is another common cause of tearing. There are other conditions that can cause tearing, such as an obstructed tear drainage system and inflammation in the eye. An eye exam would be required for a diagnosis.