Preparedness blog

Building Your Own Water Filter

By Hunter Browning
More from this author

Having no clean drinking water during an emergency can be fatal and so it's important to know how to make a water filtration system when necessary. clear ice in macro photographyWhether you already know how to make one, or you are a first timer, we'll get you familiar on designing a water filter for your needs during a crisis situation. IMPORTANT SAFETY NOTE: These DIY filters are not designed to make drinkable water. No matter how “clean” your filtered water looks, you should never drink it because it still may contain pollutants you can’t see. Drink at your own risk!


  • about 2 empty plastic water bottles
  • scissors
  • towel or paper towels(for spill clean up)
  • gauze or cheesecloth to cover the mouth of the hole
  • rubber bands
  • any materials you think would make a great filter(sand, rocks/gravel, cotton balls, etc).
  • *it's okay if you do not have all the materials needed to do this activity, get creative and substitute materials with what you have around the house).*


This can be done very easily. All you need to do for this step to prep the water you are going to want to filter. You can mix some soil with water or to make it a little harder of a challenge, you can add some food coloring, oil, vinegar, etc.


To build your own filtration system, you’ll need a filter cartridge. To do so, start by carefully cutting your water bottle in half, across the width of the bottle. Remove the cap from the bottle. Put gauze or cheesecloth over the opening and secure it with a rubber band. Turn the top half of the bottle upside down (so the part with the cheesecloth or gauze is facing down) Photo collage showing the steps to make the water filter cartridgeand place it into the bottom half of the bottle.

If you want to fit more materials in your filter, you can use two bottles. You can also use larger bottles or try other containers. *Tip: Clear containers will help you see the filtration as it takes place.* It should look something like the picture attached.




This step is just adding those items you found around the house to your newly made filter cartridge. Mix or layer the filter materials you have chosen on the top of your filter cartridge. Then, pour your simulated 'waste-water' into your makeshift water filter and observe the water that comes out. You may need to do this a couple times depending on what type of materials were used when testing the waters. You may notice that some things may need to be improved so that if you were to use something like this during an emergency situation, the water can be as clean as possible. IMPORTANT SAFETY NOTE: These DIY filters are not designed to make drinkable water. No matter how “clean” your filtered water looks, you should never drink it because it still may contain pollutants you can’t see. Drink at your own risk!


If needed, revise your filter based on what you observed during the 'testing and evaluating' stage. Consider using different types of materials and water amounts. While doing this step, you find that some materials work better that others. Keep testing and evaluating your filter. The goal is to produce as much clean water as possible during a single time through the filter.


5 months ago
4 months ago at 9:51 PM
My water purification plan: 1. Filter water through coffee filter placed in fine screen metal strainer. 2. Repeat step 1. 3. Boil water at a roiling boil in an open container for ten minutes to remove organs-phosphates and other volatile chemicals and to kill pathogens. 4. Filter the water through a large volume water filter to remove heavy metals, Water thus treated will be safe to drink. If purifying salt water for drinking purposes, add step 3A which is to distill the water through a closed distillation process. Any pot with a clamp down lid and a coiled condenser tube secured to the lip can distill water from any heat source. I plan to preheat any water used in purifying by sun exposure to cut down on the BTUs needed for boiling and distillation. This can be as simple as black plastic trash bags sitting in the sun. For general washing purposes I would eliminate step four. I think the trace amounts of heavy metals in water used for washing clothes or bathing would be the least of problems presented. If forced to, I would use salt water after boiling for washing purposes. Washed clothes in salt water while on board Navy ships and showered in salt water while on board Navy ships. Can do it again if necessary.
2 months ago at 3:28 AM
After what I went through in Texas during the winter storm, I now understand how important it is to be ready. We had no power or water for days...