What is the correct order of steps soldiers must use to treat their canteens of water?

The correct answer outlines the proper method for treating canteen water with iodine, which is essential for ensuring that the water is safe to drink. The first step, loosening the canteen cap and inverting it, allows for proper mixing of the iodine or purification tablets with the water. This step is crucial because it ensures that the water is in contact with the treatment agents effectively.

Waiting five minutes follows to allow the treatment to start working, as iodine does not purify water instantaneously; it requires some time to effectively kill pathogens present in the water. The next step involves shaking the canteen to further mix the iodine tablets with the water, which enhances the purifying process. Finally, tightening the canteen cap secures the contents and prevents any contamination during the treatment process.

This sequence maintains both the efficacy of the water treatment and safe handling of the canteen, which is vital in field sanitation practices. Understanding this step-by-step method is essential for soldiers to ensure they have access to potable water, thereby minimizing the risk of waterborne illnesses in the field.