You can go online at Costco.com and apply for a Costco Membership there by adding it to your shopping cart if you are shopping for the first time. Your membership card will be mailed to you within 7-10 days but you can actually shop at the online store immediately.
The three most common chlorine-containing substances used in water treatment are chlorine gas, sodium hypochlorite, and calcium hypochlorite.
The Good, the Bad & the Ugly News. by Nancy Hearn. The addition of chlorine in drinking water has been the standard in water treatment in the United States since 1904. Thus, for over 100 years we have trusted and relied on chlorine to purify our water and kill off any waterborne pathogens.