My husband and I bought our home four months ago. It's located on 3 acres of what we were told was "wooded" property. Now that the leaves have fallen from the trees in the backyard, we can see that we have water plants growing in certain areas. Also, we were told that the town has a pipe and the run off is getting onto our property.
Start at the Town Hall to find out the history of the property and where the water is coming from.They should be able to help you out or at least inform you.