Attempts to account for the pattern and progress of mortality decline in England and Wales in the nineteenth century have produced a literature in which something of a general accord exists over key factors involved. Historians acknowledge the influence of two broad trends of change: environmental improvements as a result of sanitary reform initiatives and nutritional improvements as a consequence of a rise in the general standard of living. Where discord has arisen is in the degree of attachment of individual historians to one or other of these trends as primary contributor. The study of mortality decline, which was the product of a complex amalgam of factors, has proved a complicated task. It is one whose outcome ultimately depends upon efforts to disaggregate and measure the influences of different factors involved. To date, attempts at the systematic measurement of certain key factors associated with mortality decline have lagged considerably behind acceptance of the importance of their measurement. An important omission has been a measure of the timing and dimensions of sanitary reform programmes which, via infrastructure development and environmental controls, had the potential to decrease the rate at which infectious diseases were transmitted. This article examines the trends which emerge from a quantification of local government expenditures on sanitary infrastructure and from attention to its phasing over time. We are concerned with two main issues: to what extent do public health expenditure data describe the public health effort, and how do trends in public health expenditure relate to the decline of mortality? Our subject is local authority sanitary reform as a factor in mortality decline and our focus is on the impact of the timing of public health expenditure rather than the reasons for that timing. We do not examine inter-relationships between sanitary reform and other factors contributing to mortality decline such as income levels and density factors. A call for a more comprehensive study of the sanitary undertakings of local government has been common amongst historians of nineteenth-century mortality decline. It has been acknowledged on both sides of the ‘nutrition versus sanitation’ debate that a probable causal relationship exists between sanitary reforms and declining mortality levels. What has been lacking is a study of sufficient scale and detail to enable comprehensive evaluation.