Question: We live in a community of 5-acre “ranchette” homes in north Phoenix. After our neighbor built a corral in his backyard, we noticed that every time there was any rain our backyard flooded. The reason for the flooding is that the construction of the corral changed the natural slope of the land so that the runoff from our neighbor’s backyard now goes right into our yard. In a heavy rain, this runoff will even go into our swimming pool and flood our back patio. When we complain to our neighbor, he refuses to do anything and says that his backyard is his own private property. Is there anything we can do to stop our neighbor causing this flooding?
Answer: Yes. The general rule of law is that a property owner cannot use his property in a manner that will cause harm to his neighbor’s property. Specifically, a property owner cannot change the natural pattern of runoff of rainwater on his property if the result will be flooding of his neighbor’s property. The liability of a property owner for runoff of rainwater is based on the 1868 English decision of Rylands v. Fletcher. In this decision, the House of Lords ruled that a property owner was strictly liable for damage to his neighbor’s mining operation due to runoff of rainwater after a reservoir failed, even though there had been no negligence by the property owner in the construction of the reservoir. The maxim is that “a man must so use his own as not unnecessarily to do injury to another” applies to Arizona surface water drainage.
Your neighbor is liable for causing flooding to your backyard and back patio. Therefore, you should be able to get a judicial injunction against your neighbor to require him to make changes to prevent runoff of rainwater into your backyard. In addition, you should have a claim for any monetary damages that you have incurred due to the flooding. These monetary damages should include the construction costs for any improvements that you may have to make to protect your property from future flooding.