The relationship between sanitary intervention and mortality decline is one of the most fundamental and enduring debates in the fields of economic, social, demographic and medical history. In Britain, one of the major challenges posed by this debate is the challenge of measuring “sanitary effort”. I will seek to address this challenge by providing new estimates of the value of the loans which were sought by local authorities and other organizations from the early-nineteenth century onwards. Previous authors have highlighted the increase in the value of the loans which were sanctioned by central government departments after 1870. In this lecture, I will provide a more detailed account of the distribution of these loans and the purposes for which they were intended, and present new data on the value of the loans which were either sanctioned by central government or approved by Parliament throughout the whole of the period from 1817 to 1914. I will also discuss the relationship between the timing of these loans and the decline of mortality in a group of areas which have previously been identified as making a disproportionate contribution to the decline of mortality during the last forty years of the nineteenth century. Three of these areas – Leeds, Liverpool, and Manchester and Prestwich – requested permission to borrow large amounts of money for sanitary and related purposes shortly before mortality rates started to decline, but this was not true of all areas. The findings highlight the complex nature of the relationship between sanitary expenditure and mortality change in different areas during this period.