How to Make a Filter for a Water Cistern

Water cisterns are an environmentally responsible way of collecting water.

Filtering cistern water is harder than filtering coffee.Filtering cistern water is harder than filtering coffee.
Unfortunately, harmful pollutants already taint much of the water that you collect from the environment. It does not make much sense to add a commercial filtration system to your cistern. The solution is to add your own filtration system to your water cistern. Natural ingredients such a sand, gravel and charcoal can be used to filter out pollutants.

Place a layer of cotton batting to the bottom of your water cistern. Depending on the size of your cistern, you will probably need 1 or 2 inches of cotton batting lining the bottom of your cistern. Use more material for larger cisterns.

Add a layer (roughly 1 or 2 inches thick) of granulated activated charcoal. Purchase this charcoal at pool supplies stores or retailers that specialize in water filtration.

Place a layer of fine grain sand (roughly 1 or 2 inches thick) on top of the charcoal. Add a layer of large grain sand to the top of the fine grain sand.

Place a layer of fine grain gravel on top of the large grain sand layer. Follow this layer with a layer of large grain gravel. Repeat steps 3 and 4 until you have a relatively thick (about 1 foot) level of material to filter the water.

Test the filtration system. Pour water into your cistern and let it filter through the layers. The water should come out clear and clean. If you notice the water is not clean or clear, add more layers to your cistern.

Things You Will Need

  • Cotton batting
  • Gravel (fine and large grain)
  • Sand (fine and large grain)
  • Charcoal

About the Author

Based in Traverse City, Mich., George Lawrence has been writing professionally since 2009. His work primarily appears on various websites. An avid outdoorsman, Lawrence holds Bachelor of Arts degrees in both criminal justice and English from Michigan State University, as well as a Juris Doctor from the Thomas M. Cooley Law School, where he graduated with honors.