Eight　disinfection　methods　were　applied　to　control　biofilm　contamination　in　domestic　hot　water　system　The　inactivation　efficiency,　responses　of　high-　(＞=　1%),　mid-　(0.1%　similar　to　1%)　and　low-abundant　taxa　(＜=　0.1%)　to　disinfection,　and　interactions　within　and　across　three　sub-communities　were　investigated.　Ultraviolet　was　the　most　effective　disinfection　method　for　total　bacteria　and　Escherichia　coli,　and　chlorine　dioxide　had　the　highest　inactivation　efficiency　on　heterotrophic　bacteria,　while　silver　ions　exhibited　poor　performance　on　all　of　them.　At　the　phylum　level,　the　responses　of　microorganisms　to　eight　disinfection　methods　were　different,　but　Proteobacteria　and　Firmicutes　dominated　in　most　samples.　Eight　disinfection　methods　had　a　greater　impact　on　the　proportion　of　high-　and　mid-abundant　taxa　than　that　of　low-abundant　taxa,　and　led　to　dissimilar　transformations　of　genera　among　high-,　mid-　and　low-abundant　taxa　in　each　sample.　High-,　mid-　and　low-abundant　taxa　of　different　samples　showed　similar　structures　and　were　roughly　clustered　into　three　Groups.　Moreover,　high-abundant　taxa　had　more　complex　internal　interactions　than　mid-　and　low-abundant　taxa,　and　mainly　presented　co-occurrence　patterns.　The　associations　between　high-　and　low-abundant　taxa　were　close,　and　some　low-abundant　genera　were　identified　as　hub　bacteria,　such　as　Parucoccus,Thioalkalispira　and　Flavitalea.　Furthermore,　a　total　of　23　potential　pathogens　were　detected　in　this　study,　and　they　mainly　showed　positive　interactions,　with　Mycobacteria　and　Streptococcus　as　keystone　genera.　These　results　highlight　the　dissimilar　responses　of　high-,　mid-　and　low　abundant　taxa　to　disinfection,　and　the　critical　role　of　some　low-abundant　genera　in　the　microbial　network,　as　well　as　the　co-occurrence　patterns　among　potential　pathogens.　(C)　2020　Elsevier　B.V.　All　rights　reserved.