Carbon water filters: pros and cons, facts and figures

Jim scowls while taking the third case of water bottles from his car trunk.

He puckers and wonders, I’m sick and tired of hauling this stuff every week. I even had to take some back last week ‘cause of that recall. There has to be a better way.

You probably feel like Jim. I sure did.

Being healthy is an important part of my life. But with so many water filtration systems, it’s confusing!

With so many options in the market, how do you know which filter is good for you?

Is the Brita jug enough? Does it really filter out all the crap?

Carbon water filters are like a sponge for contaminants

Carbon was first thought to be used as a water filtration system back in Sumerian and Egyptian times.

Carbon water filters work by a process called adsorption which means that molecules cling or adhere to the surfaces of solid bodies when they are in contact with them. In this way, carbon attracts chemicals and they “stick” to it.

Carbon water filters makes your water clean by:

1. filtering particles, such as rust and asbestos
2. removing bacteria and parasites, such as e. coli, salmonella and giardia
3. purifying away metals and chemicals, such as pesticides, chlorine, herbicides and fluoride

As the carbon absorbs these nasty chemicals, over time, they become saturated and may no longer be able to absorb more.

This is the reason why carbon filters have to be replaced because the filter will eventually become full and has to be discarded. The key is to have a high capacity carbon water filter, so replacements are every 1 or 2 years.

The EPA seems to agree with us, according to them, the following is a basic rule about water filters you should follow: carbon filters have a specified shelf life and should be replaced regularly according to the manufacturer’s instructions.

What are carbon water filters good for?

• Removal of chlorine
• Removal of organic, volatile organic contaminants– these are nasty chemicals like benzene, styrene, chloroform and carbon tetrachloride among many others. Some of these individual chemicals are in turn made up of many other chemicals when water containing organic matter is treated with chlorine.
• Pesticides – some of the most familiar ones are chlordane, heptachlor and lindane.
• Herbicides – such as Atrazine.
• Microbiological – removes cryptosporidium and other cysts and coliform.
• Turbidity –  loss of transparency due to suspended particles
• Inorganic contaminants – removal of mercury and in some cases lead.

The most effective carbon water filters are those engineered to remove inorganic compounds such as lead and asbestos, but not all of them are designed that way.

Modern, high-tech carbon filters are designed to remove contaminants that were once the sole domain of reverse osmosis systems.

What's in carbon water filters?

The tightness of the carbon or the density of it is what’s important. This means that the size of the pores within the carbon are small enough to restrict the passage of smaller size contaminants.

Some of the most severe contaminants are so small they are measured in size by microns. What’s a micron?

A section of a human hair is 0.8 microns, some forms of cysts are 0.5 microns and asbestos is 0.1. The denser the carbon block, the more contaminants it blocks or the smaller the number (in microns), the tighter the filter.

The reason these carbon water filters work so well is that they have vast surface area to bond to contaminants and so provide high quality filtration.

Also, only a specialized carbon water filter will remove fluoride, nitrates and sodium, but again this is only achieved by a high-tech carbon filter.

These highly specialized and super effective filters are solid carbon filters instead of the usual activated granular carbon filters used for example in water pitchers (Brita).

What to look out for when purchasing carbon water filters?

Look for the microns ratings. Microns is the measurement of the pore size of the filter, the smaller the number, the better it performs at removing contaminants.

However, check for “absolute” and “nominal” ratings, two words you should be aware of.

Absolute means that this number is true or complete. If the filter maker says the filter is absolute 0.5 microns, then that’s what the final pore size is. When it mentions the filter is nominal 1 micron, it means that the filter is blocking contaminants in the 1 and 2 micron range.

As we have discussed, the really good carbon water filters also contain other substances like wood and coconut shells to produce good tasting water while removing contaminants such as trihalomethane, hydrogen sulfide gas (the rotten egg smell) and chloramines.

Activated carbon is the best carbon water filter

The best carbon water filters will contain KDF/Activated carbon media to remove heavy metals, hydrogen sulfide and cysts.

When on the go, you can get a filter water bottle. This will protect you when you run out of water and have to re-fill while running errands or traveling.

Have you had issues with itchiness in your skin or unruly hair? Discover an easy way to clear your skin from dryness and eczema by trying a shower head water filter.

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Environmental Protection Agency (EPA), Health & Water Series – Filtration Facts (PDF)

Food & Water Watch, Fact Sheet, Take Back the Tap (PDF)

Cecen, F; and Aktas, O; Activated carbon for water and wastewater treatment, 1st Edition, Wiley-VCH (PDF)