About ten years ago, my neighbor told me that I could use a small manmade lake on his property. I have children who like to play there, and he is elderly, lives alone, and never swims or fishes. Indeed, he mostly spends his time in his home. We haven’t discussed my use of his lake since he initially gave me permission, and I’ve never seen him anywhere near the lake in a decade. The lake is as good as mine. Can I claim adverse possession, if the statutory period in my state is ten years?
One of the several requirements for claiming title to land based on the legal doctrine of "adverse possession" is that the trespasser’s control of the property in question be “hostile.” In your case, this means that your possession of the lake needs to be without permission, and against the interests of the true owner.
Here, even though the permission was only verbal and was given a very long time ago, your neighbor would in all likelihood be able to defeat your claim for title to the lake by adverse possession, through testimony that he expressly allowed you to be there, and was well aware that your family has been using it for a decade.
A more interesting question will arise, though, if your neighbor sells his home to a buyer and you continue using the lake for another ten years. If the buyer never bothers to get a land survey, or simply assumes that you own the lake based upon your conduct, you may eventually be able to acquire title. Apart from the element of “hostility,” your conduct otherwise seems to meet the basic elements of an adverse possession claim, which include that it have been actual, open and notorious, and exclusive for the period of time required under your state's statute.