This paper provides details and the results of an evaluation study carried out on the largest residential demand management program in Australia, the Sydney Water Corporation (SWC) ‘Every Drop Counts’ (EDC) residential retrofit program. The evaluation measured the water savings of program participants and compared them to a control group. Savings of 20.9 ± 2.5 kilolitres per household per annum (kL/hh/a) were found from statistical analysis of water meter readings of the sample of single residential households analysed. These individual savings effectively provide SWC with a potential total saving of 3,344 ± 400 megalitres per annum (ML/a) for the single residential houses retrofitted alone, i.e. 80% of the 200,000 households retrofitted to date. The evaluation identified that no ‘decay’ in average savings were found over the maximum four year period assessed. Other factors evaluated during the study included: analysis of individual water efficiency measures; comparison of savings with other evaluations; and savings related to occupancy ratio, geographical grouping, income category and defined socioeconomic categories.