Watery eyes can be due to many factors and conditions.
In infants, persistent watery eyes, often with some matter, are commonly the result of blocked tear ducts. The tear ducts don't produce tears, but rather carry away tears, similar to how a storm drain carries away rainwater. Tears normally drain into your nose through tiny openings (puncta) in the inner part of the lids near the nose. In babies, the tear duct may not be fully open and functioning for the first several months of life.
In older adults, persistent watery eyes may occur as the aging skin of the eyelids sags away from the eyeball, allowing tears to accumulate and flow out.
Sometimes, excess tear production may cause watery eyes as well.
Allergies or viral infections (conjunctivitis), as well as any kind of inflammation, may cause watery eyes for a few days or so.
Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.