The integrity of the soil treatment is directly related to factors such as: environmental conditions, controlling conducive conditions, and diligence in maintaining the installed chemical barrier (or having it immediately properly reinstalled if disruption occurs).
What can cause a barrier disruption? Over time, underground streams can break down chemical, excavation for landscaping next to the foundation of your home, adding a room onto the structure, having an in ground pool installed with subsequent utility lines run, installing a sprinkler system,
installing wooden fence posts, etc.