Document the scale and cost of water infrastructure replacement needed in OECD nations, assess the emerging contaminant threats (PFOA, microplastics, pharmaceuticals) that conventional treatment doesn't remove, and estimate the public health and economic costs of inaction.

Analysis of EPA WARN database on aging water systems, WHO emerging contaminants guidelines, and utility capital expenditure surveys across 40 OECD cities. Cross-referenced with epidemiological studies linking water contaminants to adverse health outcomes. Cost curve analysis for advanced treatment technologies.

The US water infrastructure replacement deficit is estimated at $700B over the next 20 years. Median water system age in the US is 45 years; systems with 50+ year lifespans are approaching end-of-life simultaneously, creating a replacement crisis.

Emerging contaminants — particularly per- and polyfluoroalkyl substances (PFAS) — are now detected in drinking water supplies of 97 million Americans. Conventional water treatment (coagulation, filtration, chlorination) does not remove PFAS, microplastics, or pharmaceutical residues.

Advanced treatment technologies (reverse osmosis, activated carbon, UV oxidation) can remove these contaminants but increase treatment costs by 30-50%. The public health cost of inaction — measured in disease burden and healthcare expenditure — exceeds the infrastructure replacement cost by 2-3x.