"ANSI/AWWA C220-12 (revision of ANSI/AWWA C220-07)."
"Effective date: June 1, 2012. First edition approved by AWWA Board of Directors June 18, 1992. This edition approved Jan. 22, 2012. Approved by American National Standards Institute March 27, 2012."
At head of title: AWWA standard
Electronic reproduction. Ann Arbor, MI : ProQuest, 2015. Available via World Wide Web. Access may be limited to ProQuest affiliated libraries