I would do some googling. A quick google shows that it does get used for drinking water. Alabama State for example says it's okay.
Dichlor use If you can figure how to use it correctly, I think it would be a good alternative to liquid bleach.
Dichlor is a name covering a family of related compounds. There is sodium dichlor and calcium dichlor and also dichlor and trichlor. There is also dichloroisocyanuric acid and dichloro-s-triazinetrione and more. Which one should you use? Dichlor also breaks down into various compounds which may be undesirable, but plain bleach does also.
It appears that some dichlor suppliers have NSF/ANSI certified products for drinking water and maybe you should use one of them?
NSF 60The biggest question might be how much should you use and should you test it before use? One nice thing about dichlor tablets is that it's much safer to handle than liquids and is one reason it's used for spas and hot tubs.
FWIW, food grade hydrogen peroxide can also be used and I've seen tablets with silver in it but they are expensive. Also, Giardia and Cryptosporidium are chorine resistant and won't be killed and you need a 1 micron
absolute (not "nominal") rated filter or better.