How to Make a Natural Filter for Hard Water Using Sand

A natural water filter that is capable of purifying through layers of sand and gravel is called a "slow sand filter." Such a filter can remove excessive iron and heavy minerals from hard water sources, making the water slightly softer (more like rain water) and more potable (for human consumption). Although such filters can be constructed with pipes, valves and spigots, these items are only convenience tools that can be integrated. The simplest useful form of such a filter requires very little in the way of necessary raw materials.

Things You'll Need

  • Large plastic container, minimum 20-gallon holding capability
  • 32 ozs. of hydrogen peroxide
  • 4 support posts
  • 5 lbs. of coarse gravel
  • 5 lbs. of coarse sand
  • 40 lbs. of fine sand
  • Drill with 1-inch drill bit
  • 1 clean bucket
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Instructions

    • 1

      Clean the interior of your barrel thoroughly. Flush the entire barrel completely with a known clean water source. If you are using a natural water source, boil about 10 gallons of the water at highest temperature possible for at least 30 minutes to kill all microbes that may be in it, then use this boiled water to flush clean the barrel. Mix 32 ozs. of hydrogen peroxide in the water for additional sanitizing just before pouring into the barrel. Allow the clean water mixed with the peroxide to stand in the barrel for about 1 hour, then dump out.

    • 2

      Drill two or three 1-inch holes in the bottom of the barrel, close together and in the center of the bottom. Keep the holes within 1 inch of one another. These holes are where the filtered water will fall through and into the collection bucket.

    • 3

      Set the filtration barrel on top of four support posts that are set up in a square arrangement. The posts should be placed on level ground, and far enough apart that the barrel is supported while still allowing you to slide the water collection bucket under the filtration barrel easily.

    • 4

      Pour 5 lbs. of coarse gravel into the bottom of the barrel. It should be at least 5 inches thick. Make the layer of gravel in the bottom of the barrel level.

    • 5

      Pour 5 lbs. of coarse sand over top of the gravel layer. It should be at least 5 inches thick. Make this layer of coarse sand level.

    • 6

      Fill the remainder of the barrel with fine sand, using the finest grain that you can find. Leave about one-fourth of the total length of the barrel empty at the top to leave ample room in pour several gallons of water.

    • 7

      Pour 3 or 4 gallons of water into the top of the barrel slowly so the sand isn't disturbed. Add 3 or 4 gallons of water again after about 1 hour, and then continue adding 3 to 4 gallons of water every hour until water begins to trickle out the bottom of the filtration barrel.

    • 8

      Set your water collection bucket under the barrel to collect the water once water begins to trickle out. Discard the first two buckets of filtered water, as this first water will contain small sand particles in it.

    • 9

      Add at least 2 or 3 gallons of water to the top of your filtration barrel every day to prevent the top of the sand from drying out. A layer of gelatinous slime will form on the top of the sand that is filled with beneficial microorganisms that will help in further filtering the water. This is a beneficial layer and should only be removed if it becomes so thick that water isn't able to pass through it. When this happens, carefully remove the top 2 to 3 inches of sand and discard, replacing with new fine sand.

    • 10

      Remove the bucket of filtered water promptly once full and cover to prevent it from becoming contaminated again.