The US Court of Appeals for the Fourth Circuit has ruled that damage caused by a watermain break that was concurrent with a flood is subject to a flood sublimit under an "anti-concurrent" causation clause in the property policy. The case is David S. Brown Enterprises. V. Affiliated FM. Ins. Co., No. 21-1051, 2022 U.S. App. LEXIS 439 (4th Cir. Jan. 6, 2022).

On July 30, 2016, Ellicott City, Maryland, experienced a "1,000-year rainfall," receiving four-and-a-half inches of rain in one hour, and more than six-and-a-half inches throughout the duration of the storm. The downpour caused rivers to flood and their contents to spill into the city. At that same time, an underground watermain downtown ruptured, spraying water skyward and adding to the overall water level.

Two buildings suffered damages from the water, as a result. David S. Brown Enterprises (DBS) sought coverage from Affiliated FM Insurance Co., which said the business was only entitled to $50,000 in coverage under its policy's flood sublimit.