This paper presents the findings of a longitudinal study that measures the public health impact of a multiple intervention rural water and sanitation programme termed the One Million Initiative in Central Mozambique. Data from a 2008 multiple indicator panel survey baseline is compared with results from the 2010 midline using a random selection of 1,600 households divided over 80 clusters (control and intervention communities). The study reports the impact using two statistical methods: 1) statistical analysis of double differencing; and 2) calculation of DALYs (disability adjusted life years). The results indicate a self-reported reduction from 30 per cent to 14 per cent in cases of waterborne diseases between 2008 and 2010 in the intervention areas. Regression analysis suggests that 3.1 percentage points of this 16 point decline can be attributed to interventions under the programme. Furthermore the paper noted a 2 per cent reduction in DALYs between 2008 and 2010 in the target communities.