Water Damage Not Caused by Drain Overflow

Excessive rain from thunderstorms caused interior water damage to a building through the roof. The building has a flat roof with a drain. Carrier denied the claim, citing exclusion for water that backs up from a sewer or drain. Whether the drain is not clogged, partially clogged, or completely clogged, I do not believe the exclusion applies. The water entered the building because it never reached the drain and traveled the wrong way on the roof. The water came through a seam or other opening. Is this caused by overflow or back-up? Is the loss covered or excluded?

New York Subscriber

The ISO CP 10 30 04 02 excludes loss or damage caused by "[w]ater that backs up or overflows from a sewer, drain or sump." From what you describe, the water did not even reach the drain, so it does not appear to be a backup or overflow.

However, the limitation for damage to an interior of a building caused by rain could apply unless the roof sustained damage from a covered cause of loss through which the rain entered.