Under the laws of all states in this country one cannot do something to his or her property that will adversely affect the property of another. Given what you have written, I suggest that you advise both neighbors in writing about the unwanted water now running onto your property and the need to remedy such immediately in writing.If such is not done within the demanded time period, your recourse if your property is being damaged is to file an action for a mandatory injunction requiring that the problem with water run off be rectified.