Basement flooding is a common occurrence in some areas due to excessive rainfall and saturated ground conditions. One source of basement flooding can be from structural causes such as cracks in basement walls and floors coupled with saturated soils.
Another source of the flooding can be from the backup of sewage from municipal wastewater collection systems. This usually happens when sewers are surcharged after periods of high moisture for several days duration. Water leaks into the collection system and tends to dilute the normal domestic sewage. When the carrying capacity of the pipe is exceeded, the sewage and stormwater tend to back up into customer service lines and through floor drains into basements.