Biofilms have been extensively characterised within drinking water distribution systems. However, the significance of materials on biofilm species diversity is not established. This study investigated the community composition of biofilms on plumbing materials receiving filtered and unfiltered water supplies. Biofilms were extracted from polybutylene, polyethylene, cross-linked polyethylene, unplasticised polyvinyl chloride and copper tubes in sampling rigs receiving Murray-Onkaparinga water before or after filtration. Biofilms were extracted and analysed for fatty acid composition using the FAME™ methodology. There were differences in the fatty acid profiles of biofilms and the respective water supplies, indicating differences in the attached and planktonic communities. The results also showed significant differences in the fatty acid profiles of biofilms on the polymer materials compared to copper, suggesting variations in biofilm populations on the different materials. The potential for materials to select for microbial populations has significant implications for the ecology of drinking water biofilms.