Epinions: Water Filters

Consumer-generated reviews, buying tips and advice, ratings, price information, and searchable in a variety of ways from price to product type.
http://www.epinions.com/hmgd-Small_Appliances-All-Water_Filters

HowStuffWorks: Charcoal Filters

What is activated charcoal and why is it used in filters?
http://www.howstuffworks.com/question209.htm

Treatment Systems for Household Water Supplies - Activated Carbon Filtration

1992 article from the North Dakota State University Extension Service explaining in detail what activated charcoal systems can and cannot do.
http://www.ext.nodak.edu/extpubs/h2oqual/watsys/ae1029w.htm

Home Water Treatment Using Activated Carbon

Discussion and guidelines from a 1997 article from the Michigan State University Extension.
http://www.msue.msu.edu/msue/imp/modwq/wq239201.html

HowStuffWorks: Reverse Osmosis

How does reverse osmosis work to purify or filter the water?
http://www.howstuffworks.com/question29.htm

Shower Filter Comparisons

Presents facts about the different varieties, as well as their features and benefits.
http://www.showerfiltercomparisons.com

Water Filter Comparisons

Presents compiled data on 10 products on the market. Comparison based on each product's initial purchase price, the quality and ongoing cost of the water they produce, ease of installation and ongoing maintenance requirements.
http://www.waterfiltercomparisons.com

Water Filters Guide

Offers information about water filters and filtration methods, and buying tips.
http://www.water-filters-guide.com/