There are five reliable methods for purifying water, which include boiling, distilling, filtering, using chemicals and freezing. Freezing water to purify it is the most complicated of the methods because it requires you to slowly freeze the water, and then test the results to reveal the purity. When water freezes, especially at a slow rate, there is no room for contaminants when crystals form. Therefore, the impurities are forced out, and what is frozen is a more pure form of water. This process is known to remove salt from water as well.
Fill a medium-sized container, such as a freezer-safe storage container, to the halfway mark. Place the container in a freezer. Leave the container uncovered.
Check on the water in 30-minute intervals. When the water has frozen into a large chunk, but there is still unfrozen water in the container, remove the container from the freezer.
Drain off the unfrozen water, or remove the frozen chunk of water and place it in a separate container. An ice pick or a sharp tool may be needed to puncture the ice and drain the water. The frozen water is the more purified form of water.
Test the purity of the frozen water. Use a home testing kit, which can be purchased from an online retailer or a home supply store, to test the effectiveness of the process.