How Do Water Filters Work?

How do home water filters work?  To fully understand the answer to: How do water filters work, we need to look at different types.  They all work differently.  Let us do two things: (1) Look at the different types of water filtration systems and very importantly (2) Determine which one is best for your home and family protection.
How Do Water Filters Work: Distillation

This is the oldest style of water purifier. Interestingly you will still find a few on the market.  Researchers believe that drinking distilled water is bad for your digestive system. This is because they remove the minerals from the water.  Your body needs minerals. I simply don’t like the taste.

The units are big and bulky, require major cleaning and only provide a small amount of H20 at any one time.  They are expensive.  They waste electricity, but here’s how they work.

There are two containers connected by a metallic tube typically copper.  You would put tap-water in the first container, which will be boiled to the point that all it will vaporize.  The vapor travels through the cooling tube and drips down into the collection tank at the other end.  Only things with a higher boiling point than water, like minerals, will be removed.

How Do Water Filters Work:  Reverse Osmosis (RO)

This is the most expensive style of home water filters.  They are unnecessary for publicly treated water.  They are sometimes recommended for cyst removal, but there are less expensive and better options today.

They work by forcing pressurized fluids through a porous membrane.  Anything larger than the pores will be removed.  Anything smaller, will pass through.  Neither reverse osmosis nor distillation will remove chemical contaminants.  They will however remove minerals.

How Do Water Filters Work:  GAC & Carbon Blocks

GAC or granular activated carbon is the most common alternative for home water puification filters.  They remove chlorine and some other chemicals, but the granules alone are not the best choice.  A dual stage device that includes both GAC and a multi-media carbon block will remove the widest range of chemicals, most everything that is found in publicly treated water.

The way they work is relatively simple.  As waters pass over or through the granules and the blocks, chemical contaminants are trapped on the surface of the carbon or other filtering media.  This improves the taste, smell and safety of what you are drinking.

How Do Water Filters Work:  Ion Exchange

This is a technological advancement, but still relatively inexpensive.  Ion exchange traps metallic ions, such as lead and copper, in a resin bed by creating a kind of static electricity.  But, don’t worry, it doesn’t require electricity to operate and it’s very safe.  The methodology is just very complicated and that’s the easiest way to explain it.

This stage can further improve the taste, but only removes metallic ions.  Other steps are needed to remove other contaminants.

The Best Choice for Your Home

The best home water purification systems combine a carbon and multi-media block with a submicron porous structure to remove cysts.  They also include ion exchange and GAC. 

For more information see the the author box below if you need a recommendation for the best product brand that I found.

Larry L. Taylor

4 Responses to “How Do Water Filters Work?”

  1. With love. Says:

    How do water filters work?
    Like Brita & P?r water filters.
    How do they remove chlorine, lead and other substances from the water?
    And are they really worth the money?
    Compared to regular tap water?

  2. mrsalireid Says:

    The have a couple of filters that do remove things out of tap water. There is usually a charcoal filter that removes bad odor and taste (chlorine) and then a ceramic or other type of filter to remove heavy metals and other deposits. The really nice filters can ever filter out water borne parasites like giardia.

    They’re worth the money if you want bottled water taste and quality without the eco-killing bottles. It’s much cheaper to filter and fill yourself.
    References :

  3. Toney Says:

    mrsalireid is correct.

    from a technical viewpoint, the water molecules are allowed to pass thru microscopic holes in a filter, and the larger elements/compounds are too big for the holes, so get trapped inside the filter.

    and YES, get a filter and filter your tap water – get rid of the clorine, flouride, lead, etc.

    don’t trust bottled water either – one company was sued for using non-filtered water in their bottled water
    References :
    i have a Brita, and many mfg filters will fit it

  4. Kimmie Says:

    This site has some information

    Good luck
    References :

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