How Sump Pumps Work
Drain tile can be installed inside the basement walls or outside the basement perimeter. Drain tile consists of a perforated pipe that directs the flow of water to the sump pump pit. The pit holds the water until it reaches a level that can be safely pumped out of the home to the nearest storm sewer inlet. Storm sewer inlets direct the discharge directly to the river.
New homes are required to have large egress windows to allow safe exit in case of emergency. Many homeowners are installing large egress windows for more sunlight in the lower levels. These windows all have one thing in common. The drain tile used to eliminate the rain water from these window wells are directly connected to the sump pump system.
Note that this home has two sump pump pits located at the top of the picture: one for the primary flow and the second as a backup system. The first pit will flow into the second pit if the primary pump fails. The secondary pump may have an electric pump or a battery backup system. Red dots mark some of the wooden stakes that hold drain tiles in place during the construction of this home's basement.
Check valves stop the flow of sanitary backup from coming into the home. Check valves are being installed in all new homes.