A method of treating soil adjacent a structure generally includes positioning a base unit of a treatment apparatus at a location adjacent the structure. An application tool is positioned over a first injection site. The application tool includes at least one nozzle. The base unit is operated to supply pressurized treatment liquid to the application tool. The application tool is operated to inject the pressurized treatment liquid into the soil at the first injection site without prior disturbance of the soil. The application tool is moved to a second injection site and operated to inject pressurized treatment liquid into the soil at the second injection site without prior disturbance of the soil.