Background: Federal law requires water access in schools where meals are served. Schools report high rates of water accessibility in cafeterias, but observations indicate lower adherence. Although observation is costly, it permits a more detailed assessment of a water source to determine whether it provides effective access that encourages water consumption and thus, healthy hydration for students. Methods: To offer a less costly alternative to observations, researchers developed and validated a photo-evidence tool to examine characteristics of effective school drinking water access. Two observers recorded characteristics of 200 water sources in 30 schools, including type, wear, cleanliness, and water flow, and examined obstructions and beverage promotion near sources, as well as, drinking vessel availability. Observers photographed sources which were coded by a separate research team. Agreement between observation audits and photograph coding was assessed through percent agreement, and kappa statistics and correlation coefficients. Results: Kappas indicated substantial (K > 0.60) or near perfect agreement (K > 0.80) for all characteristics of effective drinking water access with exception of wear. There was moderate agreement (r = 0.66) for water source cleanliness. Conclusions: Development and validation of a photo-evidence tool to examine characteristics of effective drinking water access in schools.