Dogs eyes need to be checked daily. If they are squinting see if there is a hair or foreign object in there. Use a cotton swab to remove the debris.
A watery discharge is not uncommon and does not indicate disease, but can continue for their life. Dogs with full or more protruding eyes are prone to tear staining.
Daily eye care is a must for constant tear staining. Normally you will notice tear staining on dog with a white coat. The area under the eye will be wet all the time and a red stain will be visible on their fur. This is because the tear duct is small. There is not much to do about that other than clean and wipe around the eyes daily so no bacteria or dirt causes an infection.
If the tear staining gets out of hand have your Veterinarian examine the problem. There are eye care specialists that can help if the staining can not be cured with medications. There are products that remove the tear stains. Be careful to get a product that is non-irritating.