This study will develop and validate a photo-evidence method to measure effectiveness of water access in schools since the Healthy and Hunger-Free Kids Act of 2010 requires that potable water be available to children at no charge during mealtimes in areas where meals are served. The aims of this study are to: 1) develop and validate a protocol for photographing and coding characteristics of effective water access in schools; 2) assess feasibility of national implementation of this method using students as data-collectors; 3) investigate potential applications of the methodology by likely end-users; and 4) explore barriers to and develop preliminary recommendations for effective drinking water access in schools. The tool development and validation study will take place in 30 schools in San Francisco, Calif., representing a variety of free drinking water sources, and the feasibility testing will take place in 50 schools representing different school types, four regional U.S. Census Bureau divisions, and different proportions of students who qualify for free and reduced-price lunch.