"Water First" School Water Promotion and Access Intervention: A Cost Analysis Study.

Background: Adequate water intake is associated with improved cognitive and physical performance, prevention of dental caries, and overweight and obesity. However, access to free drinking water in schools remains inadequate. Water First, a school-based intervention promoting water consumption, was shown effective in preventing overweight, yet its costs have not been quantified.

Objective: To evaluate the costs of Water First from the school's perspective over one academic year.

Design: Secondary analysis of a cluster-randomized clinical trial assessing the cost of Water First.

Participants/setting: Six public schools in the San Francisco Bay Area in the 2018-2019 academic year, with an average of 578±69 students per school and 110±2 fourth-grade students in intervention schools, and 508±190 students per school and 101±5 fourth-grade students in control schools.

Intervention: Schools were randomized to receive water dispensers and stations in cafeterias and high-traffic areas and a schoolwide water promotion campaign (school-level intervention). Fourth-grade students and teachers received reusable water bottles, lessons, and materials for school and home (class-level intervention).

Main outcome measures: Activities, resources, and the value needed to implement the school- and classroom-level intervention were systematically captured over one academic year, including labor, materials, and utilities costs.

Statistical analysis: The intervention costs per school and per student were estimated by summing the component-specific costs. Results are presented for both school- and classroom-level interventions in 2023 USD.

Results: The Water First intervention costs $20 per student for the school- and $131 per student for the classroom-level intervention over one academic year. Accounting for the useful life of the installed water stations and dispensers beyond one year, the annualized cost of the school-level intervention was $11 per student.

Conclusions: These cost estimates provide useful insights for schools and stakeholders to plan and implement effective school-based interventions that promote access to drinking water.