Assembly Bill 129 mandates that all public and private schools in Wisconsin develop a comprehensive drinking water management plan within 15 months of the bill's enactment. This plan must include the locations of filtered bottle-filling stations and faucets, ensure at least one filtered bottle-filling station for every 100 occupants, and establish a schedule for regular water sampling and testing for contaminants such as lead, PFOA, and PFOS. If testing reveals lead levels between one and five parts per billion, schools must check filters and retest the water. If levels exceed five parts per billion, schools must shut off the water outlet, replace filters, and notify parents and guardians of the situation while developing a remediation plan.

By August 1, 2027, schools are required to install the specified filtered water stations and faucets, shutting off any non-compliant water outlets. The Department of Public Instruction (DPI) is tasked with assisting schools in meeting these requirements, including providing templates for the management plans and offering training on water testing protocols. Additionally, DPI is authorized to award grants to help schools cover compliance costs, although the bill does not allocate specific funding for these grants.