During the years that I was the EMA director of a city I used to include a link to the Clorox Co. directions for purifying water on my department webpage, despite the fact that the company kept changing the URL. Today I had to search 30 minutes to find it.
I should note that they only give directions for two of the 20 odd varieties of bleach they sell. Based on stores in my area regular Clorox is not obtainable. Many of the varieties contain additives that mean they cannot be used for potable water and the percentages of Sodium Hypochlorite in all varieties is always expressed in a range: "1-5%", "5-10%", "10-15%"
As to the comment as to C Rations having a finite life, I recall during the period 1965-1968 eating C Rats that had been packed between 1943 and 1945. All were edible and no one got sick. (the eggs in the canned scrambled eggs and ham had turned a but green but were edible)