Sump Pump Failures
Homes that have sump pumps will sometimes have drainage systems draining into the sump well. The operation of the sump pump in these types of systems is not as big a priority as the actual drainage system itself.
Here is why.
Interior and exterior drainage systems are designed to drain the water away from the interior of the home. Exterior systems drain the water away from the home and interior systems drain the water under the home and collect the water in a well. Exterior systems require no well, but exterior systems rarely last past 2-5 years and many actually fail immediately. Interior systems require a pump to lift the water up and outside. In these types of systems it is the actual drainage system that is doing 90% of the work. It is the drainage system that is allowing a path for the water to go under the house and or move from one spot to another under the house until the water table naturally lowers again. If the sump pump fails, and if given enough water, the water will drain upward out of the sump well. This will flood the area around the well. This is obviously not ideal, but it is a far better scenario than if there was no drainage system at all. Comparatively, without any drainage system the water would leak from the floor wall seam around the entire perimeter of the basement. This is much more destructive than a single sump pump failure in the presence of a operational drainage system. Still, no one wants even the smaller problem of a failed sump back up.
There are many. And they each depend heavily on the specifics of the building area where the work will be performed. Consulting a drainage expert would always be advised. Failed systems can be a mess and preventing a back up is part of good system design.