Absolutely!! And it's supported by virtually every finding/study/agency, etc..

Generally, bleach (sodium hypochlorite) is considered the least effective with iodine being better and the chorine dioxide treatments being best (amongst chemical treatments). There are some thoughts that bleach is ineffective partly because of the recommended doses, i.e., giardia and crypto might be killed off at higher levels of bleach than normally suggested for water treatment. But then you run into the issued of convenience, toxcity, and 'taste.' Interestingly, there are instances of giardia in chorine-treated municipal water but a drop-off/elimination of giardia when those municipalities switched to chlorine dioxide treatments.

Bleach and iodine are effective for backpackers because much of back country water is free of giardia and crypto. And then there's the issue that, just because you drink such contaminated water, it does't mean you'll get sick from it. Finally, there are plenty of 'intestinal upsets' that are not giardia/crypto or even water-based. One study attributed the majority of such illnesses to personal hygiene, e.g., lack of hand washing.

Bleach is better than nothing...but there's much better choices out there. If one is going to use bleach, make sure it's the unscented kind.

FB