Does the retaining wall exhibits any of the following symptoms:
- Tilt
- Lean
- Bulge
- Depression
- Active water leak
If so then there is hydraulic water pressure behind the wall. That’s just a fancy way of saying there is water behind the retaining wall that is pushing or undermining the footings. In that case, yes there is an active condition that needs to be dealt with soonest possible.
If the wall has a vertical crack and has just sunk or bent at that crack location, then it is more an issue of settlement rather than water pressure. In this case it means that the soil was inadequately compacted during construction or subsurface water has eroded the footing causing the ground to settle more than anticipated. In these situations, the remedy depends on the age of construction. If the wall was built, say in the 1070’s, it probably means that it has settled into its final position and no further action will be required by the buyer, other than to mortar the crack opening.