This standard describes dry-form ferric sulfate and liquid ferric sulfate for use in the treatment of potable water, wastewater, or reclaimed water. C406 provides minimum requirements for ferric sulfate, including physical, chemical, sampling, packaging, shipping, and testing requirements.

Major revisions made to the standard in this edition include the following:

Inclusion of a requirement for compliance with the Safe Drinking Water Act and other federal regulations.
Inclusion of a requirement for tamper-evident packaging.