Supplying clean water to your household is becoming an increasing concern as
people learn more and more about potential impurities found in their tap water.
Old corroded piping systems, groundwater leaching, runoff, PFAs, and other
hazards add heavy metals, pesticides, pharmaceuticals, and other contaminants.
One way to improve the quality of your water is through the use of filters with
carbon media. Here is an overall guide that covers what carbon water filters are,
how they work, types, maintenance, and more.
What are carbon filters?
Filter cartridges that use carbon media are carbon filters. Carbon media is usually
composed of natural, eco-friendly materials like wood, nutshells, or coal. Most
carbon water filters on the market today are composed of coconut shell carbon,
which has a reputation for providing better tasting water than other media types.
Carbon media can then be contained in various filter forms, such as in a plastic
cartridge, combined with other media like sediment filter media, or in a mesh
filter. The cartridge can then be inserted into a filter system to begin filtering
water.
How do carbon filters work?
Unlike a filter such as a sediment filter that captures physical particles within the
media, carbon water filters use adsorption to reduce impurities. Think of carbon
media like a sponge, that soaks up the water and stores the impurities in pockets of
carbon. All carbon filters will absorb chemicals like chlorine and reduce turbidity
from water for an improved taste, odor, and appearance. A touted benefit of
carbon over other filters is that it traps the harmful impurities while allowing
beneficial minerals like calcium to remain in water.
Main Types of Carbon Filters
Generally speaking, carbon water filters can be broken down into two types:
carbon block or CTO filters, and GAC (granular activated carbon) filters. Both
types utilize activated carbon to reduce chlorine and other chemicals, VOCs
(volatile organic compounds), pesticides, pharmaceuticals, and heavy metals like
fluoride. Carbon block filters utilize loose carbon blocks of very fine carbon
powders that are compressed together to create a larger surface area and increased
filtration of smaller contaminants.
The composition even allows for some filtration of particles like sediment. GAC filters
use loose granules of carbon to absorb impurities, allowing for a better flow rate. GAC
filters are commonly used as a polishing filter to guarantee better water after previous
stages of filtration, which often include a carbon block filter. Another carbon filter
option is catalytic carbon, a specialized filter that utilizes highly activated carbon for
enhanced filtration of chlorine and chloramines over other filtration options.
How to Choose the Right Carbon Filter
Choosing the right carbon water filter for you depends upon your filtration needs
and the abilities you have to install different filter systems. If you need enhanced
filtration of contaminants a carbon block filter may be best. However, if basic
activated carbon filtration is enough and you need more water flow, GAC filters
may be better. GAC filters also tend to be a lot more affordable than carbon block
filters, as the more involved carbon block manufacturing process creates a higher
price. Catalytic carbon provides the most advanced filtration, but costs the most
and offers the least amount of different filter options, mostly being limited to
larger cartridge filters.
Another consideration is the form. Carbon water filters can be found in pitcher
filters, refrigerator filters, undersink filters, whole house filters, and more. Pitcher
filters are the most affordable option but provide limited amounts of filtered
water. Whole house filters combine one or more stages of filtration for filtered
water to the entire home.
How often should I replace my carbon filter?
How often you replace any water filter depends upon a number of factors unique
to your situation, including water quality and usage. Water with a higher number
of contaminants will require more frequent cartridge change-outs. In general,
most carbon filters last for about 6 to 12 months. A good rule of thumb is to
replace your filter if you notice a sudden, steep decrease in water pressure.
Can I clean and reuse a carbon filter?
Washing and reusing a carbon filter is not recommended. While you may be able
to wash away most of the absorbed impurities, you will not be able to reactivate
the carbon. Plus, as a carbon filter is used the carbon begins to wear out and
release carbon fines into the water supply. They simply are not made to be reused.
Where can I install carbon filters?
Inline carbon filters can be hooked up to a refrigerator or under the kitchen sink.
Larger cartridges can be installed in stand-alone housings or put in filter housings
within an undersink filter system, RV water filter, reverse osmosis filter system,
whole house system, or more. Carbon water filters are a highly flexible media that
provide a number of different filtration choices.
Do carbon filters remove viruses?
No, a carbon filter is not designed to filter viruses, bacteria, or TDS (total
dissolved solids) from water. This is because as mentioned before, carbon reduces
impurities by adsorption, not capturing solids. To reduce viruses and bacteria, a
UV filter or ceramic filter is a better choice. For reduction of TDS like sodium
and other minerals, a reverse osmosis filter is recommended. However, some
people see carbon filters not reducing certain TDS like minerals as a benefit.
Are carbon filters expensive?
How much a carbon filter costs will depend upon the type of filter you choose.
Carbon water filters found in water pitchers and inline refrigerator filters are
relatively affordable. Carbon block filters, as mentioned before, cost more than
GAC filters. Catalytic carbon water filters tend to be on the pricier side. The wide
variety of carbon water filters make them an option for almost any price point.
What maintenance do carbon filters require?
In general, a carbon water filter requires regular replacement to keep up water
flow rates and to keep producing quality water. In addition, it is usually
recommended to flush carbon water filters when first installed or replaced. This is
because the fresh filter will shed carbon fines at first, which are harmless to
consume but can make water appear cloudy. The fines may also clog up other
filter cartridges in a water filter system. Flushing for about 3-5 minutes until water
runs clear before use is typically sufficient.
The Bottom Line
Carbon water filters are a versatile, effective choice for improving the taste, smell, and overall look of water. They come in a variety of filter options to fit the
filtration needs of almost any household. Choosing the right carbon filter can
help you be well on your way to getting cleaner, clearer water.