Actually, bleach is not only regularly and widely used as a disinfectant, it is Recommended as a disinfectant, by many, many agencies. It is the first item recommended to disinfect drinking water,after boiling, as a matter of fact, by practically every disaster management plan out there. One example:
http://ndep.nv.gov/bsdw/docs/disinfect_drinking_water.pdf
HOW TO DISINFECT DRINKING WATER
1. Boil water vigorously for 2 to 5 minutes, or
2. Disinfect water using common unscented liquid household bleach. Read the label
for instructions or use the instructions below:
A. Use 2 drops liquid bleach per quart of water.
B. Mix thoroughly and allow to stand for 30 minutes before using.
C. Water should have a slight chlorine odor-if not, add one more drop of
liquid bleach.
Note: For larger quantities of water, see the chart below:
Using common unscented liquid bleach (5% solution)
Another:
http://www.scchealth.org/docs/ph/ph_docs/pdfs/disinfecting_well_051107.pdf
Water of uncertain bacteriological quality should be disinfected
before used for drinking or in food preparation. Boiling water will
kill disease-producing organisms that may be present, but boiling
large quantities of water is inconvenient and impractical. It is
usually more practical to disinfect a water supply with an oxidizing
agent such as chlorine.
There are several commercial products that may be used for
disinfection water. These include dry chlorinated lime (also called
bleaching powder), household bleaches such as Clorox or Purex
and calcium hypochlorite compounds such as HTH, Perochloron or
B-K Powder.
The amount of chlorine compound required to make water safe
varies according to both quality and amount of water to be
treated. The general rule is to add enough disinfectant to give the
water a distinct chlorine odor and taste. The odor and taste will
disappear within a few days following treatment.
Another:
Cleaning and disinfecting child care practices
Recipe for Bleach Disinfecting Solution
(For use in bathrooms, diapering areas, etc.)
1/4 cup bleach
1 gallon of cool water
OR
1 tablespoon bleach
1 quart cool water
Add the household bleach (5.25%
sodium hypochlorite) to the water.
Recipe for Weaker
Bleach Disinfecting Solution
(For use on toys, eating utensils, etc.)
1 tablespoon bleach
1 gallon cool water
The list could go on like that for a long, long time. Google disinfecting water bleach. I have had a water well for most of my life, and the standard is to add bleach to the well for disinfection. Emergency directions for storing water in case of emergency tells you to add the recommended amount of bleach to any water you want to store that did not come sealed. Etc. etc. Like many other things in life, just because too much is toxic does not mean that the right amount is not beneficial.