I tested country water and compared our catchment

[terracore]

Before one starts dumping chemicals into drinking water remember:

Chlorine and bleach aren't the same thing, and:

I don't use chlorine or bleach in our water supply for a number of reasons, but I do remember reading that in the food processing business, where bleach is required to be used, the regulatory authorities require specifically "food grade" bleach be used. And at the time, only the Clorox brand was registered with the EPA for this purpose. Bleaches you see in the laundry aisle may have additives or formulations that aren't safe to be added to drinking water.

"Key Difference: Chlorine is an element and has the atomic number 17. It belongs to the halogen group and is the second lightest halogen after fluorine. It is a strong oxidizing agent. Bleach is any chemical that is used in order to remove color, disinfect or whiten objects...The most common types of bleaches that are available in the market are sodium hypochlorite and calcium hypochlorite, both of which are made using chlorine."

Lastly, chlorine bleach is unstable. It has a shelf life of 6 months after which it becomes 20% less effective per year. Eventually it becomes salt water.

ETA: for accuracy

[MarkP]

Over the weekend I measured the chlorine in my catchment system. The water in my "clean water" tank showed a hint of color, about .5 ppm worth. The water from 36" down also showed some color, barely. Probably not even .5 ppm. After testing I sprayed a cup of chlorox across the top of the tank (mesh cover). Yesterday there was very little increase in chlorine coming through the pick-up and no noticeable increase at 36". Today the water in the system is about 1 ppm and the water from 36" is a solid .5 ppm. All in all the first shock treatment of 2 cups after a long period of going commando got used up rapidly but after that a cup per week seems to keep the top couple of feet of a 15' diameter tank treated.