Retaining walls
A retaining wall is a structure to support or hold back earth and is often found between properties where the ground is at different levels.
Installation of retaining walls are more likely to require a Development Application, but there are some exceptions listed in Parts 1 and 2 of State Environmental Policy (Exempt and Complying Development Codes) 2008.
A Council Planning Advisor can provide guidance.
If you are struggling to reach an agreement with a neighbour regarding a retaining wall, LawAccess NSW provides guidance on the next steps.