The Lead Service Line Replacement Cost Calculator (LSLRCC), developed by Environmental & Public Health International (EPHI), is a free, multilingual tool that helps utilities, municipalities, and public health organizations accurately model, budget, and plan lead service line replacement projects. LSLRCC supports compliance with the EPA Lead and Copper Rule Improvements (LCRI) and planning under the Bipartisan Infrastructure Law (BIL). Recognized by the United Nations Environment Programme (UNEP), the tool advances safe drinking water equity, infrastructure resilience, and public health. LSLRCC promotes measurable progress toward eight key UN Sustainable Development Goals (SDGs 3, 6, 8, 9, 10, 11, 16, and 17), addressing health, water quality, economic growth, innovation, equity, resilient cities, good governance, and partnerships. The tool empowers governments and utilities to prioritize lead service line replacements, reduce lead exposure in drinking water, and enhance accountability in public works. EPHI welcomes sponsorships from public, nonprofit, and private partners aligned with our mission to expand safe drinking water access and protect public health. LSLRCC is designed for practical, real-world application, making it a vital resource for municipalities, utilities, and regulators committed to sustainable, equitable water infrastructure planning.