Protection the basement doesn't have yet
A second pump for when the first can't run
A battery backup sits in the same pit, a little above the main pump, and takes over when the power cuts out or the main pump fails. A water-powered backup does the same job on city water pressure, with only an alarm battery to keep up. The battery backup sump pump page compares the two.
A pit where there isn't one
Water seeping in where the floor meets the wall, in a basement with no pit, means groundwater has nowhere to go. A new sump pit installation means cutting the slab, setting a basin, tying in drain tile and running a discharge line outside.
Plumbing that sends groundwater the wrong way
Footing drains on the sanitary sewer
In some older houses the drain tile around the footing was piped into the sanitary sewer instead of a sump. In a heavy storm that clean groundwater crowds the sewer line. Footing drain reroutes explains how those drains get cut off the sewer and sent to a sump pit.
A sealed pit under the basement bathroom
An ejector pump lifts toilet, shower and laundry water up to a sewer line that sits higher than the basement floor. The pit is sealed and vented because it holds sewage. Sewage ejector pump repair covers what fails and how to tell an ejector pit from a sump.