I own a 50 year old house in Eastern Canada. My house always had a slight seepage in the basement. Not significant to cause an alarm but annyoing enough to prompt me to do something about it.
Yesterday I pryed off old "finishing" (essentially plywood nailed to framing studs) and discovered a hole in the basement wall. The hole is wide an shallow. I'd say about 1.5" wide and about 3/4" high. I'm fairly sure now that this hole is the source of my seepage. Like I said, the seepage was never significant so the presence of the hole could easily have caused it. I can't verify whether the hole goes to the outside but it is at least five inches deep as I could stick my entire finger in it. I suspect the hole goes all the way through the wall.
My question is this. What caused the hole to appear in the first place? Could it have eroded? It does not seem likely to me as the edges of the hole seem quite sharp.
Is if realistic that the hole was gnawed by a norway rat or another type of rodent? We had some rat-like poop in the basement but not near the hole.