» Epinions: Water Filters and Purifiers    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/otdr_Camping_And_Hiking-Water_Treatment

» Giardia Water Filters    Tips and recommendations on avoiding giardia and using water filters while backpacking, trekking and hiking.    http://giardiaclub.com

» Outside Online - 2002 Buyer's Guide: Water Filters    Outside Magazine's guide to water filters and portable hydration systems, including general information plus reviews, descriptions, and photos of the gear tested by their experts.    http://outside.away.com/outside/buyersguide2002/water_filters/index.adp

» TheBackPacker.com    Reviews of water filters, as submitted by the users.    http://www.thebackpacker.com/gear/water_filters/