The Healthy Drinking Water Affordability Act, or Healthy H2O Act, amends the Consolidated Farm and Rural Development Act to create a new grant program. This program, known as the Healthy Drinking Water Affordability Assistance Program , is designed to improve drinking water quality for eligible end users in rural areas. It specifically targets communities and households impacted by various naturally occurring and human-caused contaminants, such as lead, arsenic, and perfluoroalkyl substances (PFAS). The grants provided under this program can be used for the purchase, approved installation, and approved maintenance of eligible drinking water quality improvement products , including certified filter components. These products must be third-party certified to meet specific health contaminant reduction standards. The program also covers the costs of qualified water quality tests necessary to identify contaminants and support product selection. Eligible end users include homeowners, renters, owners of multi-unit residential buildings with 25 or fewer units, licensed child-care facilities, and other facilities located in rural areas. To qualify, an end user must demonstrate a need through a qualified water quality test or other satisfactory documentation showing the presence of health contaminants. Additionally, grant recipients must have a household or business income not exceeding 150 percent of the median nonmetropolitan income for their State or territory. Nonprofit organizations are also eligible grant recipients and can use funds to offer voluntary water quality tests, analyze results, assist end users in selecting appropriate response options, and coordinate professional installation. The Secretary of Agriculture is tasked with administering the program, prioritizing funding for eligible end users relying on private wells, and improving local capacity to respond to contamination challenges. The bill authorizes an appropriation of $10,000,000 for each of fiscal years 2026 through 2030 to carry out the program. It also mandates annual reports to Congress, which will identify barriers to safe drinking water, analyze conditions impacting grant recipients, assess available technologies, and provide recommendations to increase access to grants and related services.