All information can be found HERE
USA Swimming Water Depth Rule Change
Special Notice to Members of the USA Swimming House of Delegates & All USA Swimming Clubs: Pursuant to USA Swimming Rules 504.8, the USA Swimming Board of Directors has decided to amend Rule 103.2.2 (page 43 of the 2010 Rules & Regulations) which specifically applies to teaching racing starts to provide as follows:
103.2 WATER DEPTH-
This decision has been made with the advice and consent of the Safety Education Committee, the Rules and Regulations Committee, and legal counsel. The purpose of this action is to further protect novice swimmers from accidental bottom strikes while they are learning to execute racing starts. This change was effective immediately on February 19, 2007.