It doesn't matter how water or flooding enters, the real question is what to do after a flood. Homeowners in Aurora have flooding from rain storms, plugged drains, failed footer drains, failed sump pump, and broken pipes. So, the first task is always to stop the water and get rid of the water as fast as possible. This is were a wet vacuum can be helpful after the bulk of the water is pumped out.
It takes mold about 48-96 hours to start when conditions are wet, so the quicker things are dried out, the less problem there will be with mold and mildew.