If you have not been able to answer your questions with our site, the following list of alternate learning tools on the Internet may help. Please note, inclusion on this list does not constitute endorsement of any kind.

http://www.nsf.org
NSF International, founded in 1944 as the National Sanitation Foundation, is known for the development of standards, product testing and certification services in the areas of public health safety and protection of the environment.

http://www.wqa.org
The Water Quality Association (WQA) is the international trade association representing the household, commercial, and industrial water quality improvement industry.

http://www.ntllabs.com
The National Testing Laboratories, Ltd. is the Nation's largest independent laboratory specializing in the analysis of drinking water.

http://h2otest.com/index.html
Suburban Water Testing Labs is a nationally recognized independent lab, specializing in home drinking water testing since 1963.