Here are some suggestions.
(1) Discuss the matter with your buyers agent
(2) Discuss the matter with your attorney and make sure you order your own survey (which I am assuming you may have already done.
(3) Interview the neighbors, they can hold a plethora of information; and in my view most importantly
(4) Go to the township (or ask your buyer's agent to do so) to determine their position and/or there are any past permit or report issues regarding issues with this basin.
Francesca Patrizio, Broker Sales Associate, ePro