COMMENT FROM DEBRA: The response I gave was based on the information given about the filter on Zerowater's own website. They themselves do not mention that their unit contains an activated charcoal filter on their website.

I found a review of the filter on Treehugger at http://www.treehugger.com/files/2008/09/zero-water-filter.php, which states that their filter contains:

STAGE 1 A 20 to 50 micron filter designed to remove suspended solids such as dust and rust that make your water appear cloudy.
STAGE 2 Activated carbon that is Class I rated for chlorine.
STAGE 3 A water distributor screen that also removes suspended solids.
STAGE 4 Specialty resins that reduce levels of metals such as lead, mercury, and chromium in your water.
STAGE 5 A 1 micron filter designed to removed suspended solids.

Note that three out of the five filters are there to remove suspended solids.

To answer your question about activated carbon, yes, activated carbon does remove chlorine and other carcinogens. Somebody else posted elsewhere on this blog that they contacted Zerowater and was told that it also removes some chloramines, but the filter cartridge would not last as long.

I've been researching water filters for more than twenty years, and I can tell you that this is a very small amount of carbon. Certainly it might pass a test when it is new to remove chlorine, but the cartridge becomes less and less effective the more you use it. A cartridge this small would need to be changed quite frequently.

If this really was a filter designed for chlorine removal or anything else, why not advertise that fact on their website? What they are promoting is TDS removal.

A water filter such as this certainly reduces plastic bottles, and you can return your cartridge to Zerowater for recycling, but as water filters go, you would be better off going down to Home Depot or Lowe's and buying an inexpensive undersink carbon filter.