what is this watery stuff leaking from my dogs eyes all of a sudden?

lately there has been a couple of stray dogs getting in our back yard. They dug a hole from the front yard to get in the back under the fence, and now for the last couple of days my dog has this liquid running down his face from his eyes......it is not thick or anything, it is very thin, almost like water. I am wondering if my dog has contracted something? Our dogs are indoor dogs, and we only let them out a couple of times a day for about 10 minutes unattended.

Sounds like normal tear production. If it's yellow or greenish then you would worry of infection.Is the white of his eyes really red or blood shot? Does he squint? Pawing at his eyes alot? Any of these yes, call the vet for exam/meds.

Discharge maybe.

My dog crys all the time. Literally tearing up. It happens to him when he gets too excited. You can always call your vet if your too excited.