If your system is making a significant change to its disinfection practice, it must calculate a disinfection benchmark using the procedure specified in the following table. ------------------------------------------------------------------------
To calculate a disinfection benchmark your system must perform the
following steps-------------------------------------------------------------------------Step 1: Using the data your system collected to develop the Disinfection
Profile, determine the average Giardia lamblia inactivation for each
calendar month by dividing the sum of all Giardia lamblia inactivations
for that month by the number of values calculated for that month.Step 2: Determine the lowest monthly average value out of the twelve
values. This value becomes the disinfection benchmark.------------------------------------------------------------------------