variety of methods that use chemicals ranging from test strips,
calibrated color scales, to portable colorimeters. The user
should be aware that some chlorine test kits do not measure
free chlorine (recommended for water potability). Test kits
used for pool chlorination (based on the OTO method)
measure total chlorine, not free chlorine and are therefore not
recommended for use in testing potable water storage tanks.
Tests kits that use the DPD-1 method are recommended to
test free chlorine in potable water. There are three types of
kits that can be used to measure total (not recommended) or
free residual chlorine (recommended) (CDC, 2012) in order
of increasing cost: