How to Freeze Water to Make it Pure


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.

Step 1

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.

Step 2

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.

Step 3

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.

Step 4

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.

Tips and Warnings

  • Keep in mind that the most reliable way to purify water is to boil it, filter it, or use chemicals to clean it. Certain bacteria can survive freezing conditions.

Things You'll Need

  • Water
  • Square container
  • Freezer
  • Ice pick or sharp tool
  • Home water testing kit


  • How Everything Works: Water Purification
  • Water, Water, Everywhere: Water Purification
Keywords: freeze water, freezing water for purity, make water pure

About this Author

Desi Crall has a B.A. in Political Science from California State University Sacramento, and is currently a graduate student of Elementary Education at the University of Phoenix. Desi has worked as a freelance writer for three years, with articles and blogs appearing on sites such as,, and

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