How Long Does Carbon Last?


Tom asked the following question (evidently while also trying to make a statement) about a subject on which he has very litle knowledge:

You say you beat Lifesource hands down but nowhere on your site can I see how many gallons your system is rated for. Lifesource Elite is rated for 2.2 million gallons about 12 years for a typical family of three. Your system only indicates 7 year expectation but how many gallons?  If only 500,000 gallons that won’t make it 4 years in a typical family home and at your price if I have to by 4 systems over the same amount of water, how does you math work out to being less than that of Lifesource?


OK, I am not saying this to be mean or condenscending, but you obviously have little knowledge of carbon, so let me educate you a bit! There are many things which impact the life of granular activated carbon, including choosing the correct type for your application and using the correct pretreatment options. After knowing the carbon basics, it’s important to research exactly which type of carbon will best fit your application.

Carbons made from different raw materials possess vastly different pore size ranges, which lend themselves toward certain applications.  Carbon can be made in many different ways and each type is best suited to a different application. Choosing the correct type can make a difference in carbon’s lifespan and system effectiveness. Carbon is very effective at removing many contaminants, including the following:

  • Residual chlorine and monochloramine
  • Taste and odor causing organic contaminants
  • Volatile organic compounds (VOCs)
  • Trihalomethanes (THMs) and other halocarbons
  • Endocrine disrupting compounds (pharmaceuticals, personal care products, etc.)
  • Chloramine, hydrogen sulfide and hydrogen peroxide (removed by catalytic carbons)

While activated carbon can act as a physical filter, it is best for it to act as an adsorbent for dissolved organics, not the filtration of solids. A carbon can filter out particles down to 5-10 microns in size, but if the water contains a significant amount of suspended solids larger than this size, filtration ahead of the carbon bed will dramatically help to improve its service life.

Activated carbon, by going through the process of filtration, eventually loses its adsorption efficiency. This happens when the pore structure of the carbon is so full taht it cannot adsorb any more impurities. At this point, the carbon is typically deemed spent, and would need to be replaced.

I could write for hours about this subject, but I have read dozens of whitepapers and literature about carbon life and have worked with carbon for most of my 45 years in the water treatment business and I can tell youthat I do not believe that a tank of carbon will last 2.2 million gallons or 12 years, but they evidently have a certificate that says it has a replacement service cycle of 2.2 million gallons.  So there is that.

The type of contaminants which may be in your water can dramatically affect the carbons’ ability to remove the contaminants.  We do not put a gallon number on the carbon, but rather say that typically carbon needs to be replacedf every 4-6 years. That’s a fair, accurate and honest estimate.  According to NSF International, carbon filters trap some contaminants while other bacteria adhere to the surface of the carbon. If the carbon filter is not replaced often enough, bacteria can build up on the surface of the carbon and fill the entire surface.


At US Water Systems we use a blend of coconut shell granular activated carbon and catalytic coconut shell granular activated carbon.  This removes a very wide spectrum of contaminants and we typically use vastly more carbon which results in extended life due to “prolonged contact.”

Our  Fusion Superfilter, which has a 7-year warranty on the valve and electronics and a Lifetime Warranty on the tanks. I would NEVER allow carbon to be in the same tank for 12 years. We tell our customers to replace the carbon every 4-6 years and we are comfortable with that time table. We would rather underpromise and over-deliver.


This article has 6 Comments

  1. Mark,
    Please educate me. My goal is to have filtered soft water. I want to remove the hardness to reduce/remove the water spots but I also don’t want sodium in it. Why not first soften the water then filter to remove the sodium plus all the other contaminants ? Will it taste funny without the calcium/magnesium?

  2. You may or may not know a lot about this stuff – I’m not going to comment on that – but your delivery is arrogant and antagonistic. I’ve worked with a roofer that spoke the way you write and it was a horrible, terrible experience. I simply do not trust someone who behaves this way. The sad thing is, you may be 100% correct but I have no way of knowing and you’ve lost credibility.

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