1. ASCE (American Society of Civil Engineers) 2009 2009 Report Card for America's Infrastructure www.asce.org/reportcard/
2. Conley , L. 2012 Paying for Infrastructure American Cities and Counties
3. Estimated use of water in the United States in 2005
4. Conservation and Drought Water Rates: State-of-the-Art Practices and Their Application;Rawls,2009
5. Residential Water Use Trends in North America;Rockaway;Journal AWWA,2011