This bill amends federal water pollution control law to establish a grant program specifically for Hawaii to help households upgrade or replace small-capacity cesspools, which are underground sewage systems serving single-family homes. The program would provide federal grants covering 75 percent of project costs to convert cesspools to septic systems, connect homes to municipal treatment facilities, or transition communities to shared wastewater systems, along with funding for workforce training and technical assistance related to wastewater management. Eligible households must be located in municipalities that meet Hawaii's affordability criteria, and the bill prioritizes projects addressing cesspools that pose the greatest health and environmental risks. The legislation authorizes $20 million in federal funding annually for fiscal years 2028 through 2032, with up to 2 percent of that amount available for administrative costs. Grants would be administered by the Environmental Protection Agency and distributed to Hawaii's state government or local management entities with the capacity to oversee decentralized wastewater systems.