This standard describes gravel, high-density gravel, silica sand, high-density media, anthracite filter materials, and the placement of the materials in filters for water supply service application. ANSI/AWWA B604, Standard for Granular Activated Carbon, addresses use of GAC as a filter medium and as an adsorbent. Major revisions made to the standard in this edition include the following: added definition of anthracite in accordance with ASTM D388; added Table 7 to clarify maximum sample sizes allowed on individual sieves during sieve analysis; added references within Appendix A-Bibliography; added Appendix C with language related to particle size distribution classification that was in the foreword of the previous revision to the standard; and, added Appendix D with language related to Filter Media Support Gravel Size and Layer Depth that was in the foreword of the previous revision.