Decentralized　periodic　event-triggered　control　can　reduce　the　working　time　and　data　transmissions　in　the　sensor　nodes　for　feedback　control　loops,　making　it　suitable　for　wireless　networked　control　systems,　especially　those　with　large　physical　scales,　such　as　smart　water　distribution　systems.　However,　the　design　of　this　control　approach　requires　accurate　system　model,　which　is　normally　difficult　to　obtain.　In　this　work,　we　assume　a　digital　twin　of　the　original　system　can　be　obtained　by　some　modeling　and　simulation　tools,　for　example,　Simscape　in　MATLAB/Simulink　for　water　distribution　systems,　and　thus　present　an　event-triggered　controller　design　approach.　We　first　present　the　design　of　such　an　event-triggered　controller　for　the　digital　twin;　and　then　analyze　the　condition　under　which　if　both　the　original　system　and　its　digital　twin　can　be　satisfied,　the　same　controller　can　work　for　the　original　system　and　some　type　of　stability　can　be　guaranteed　at　the　same　time.　The　proposed　approach　is　applied　in　a　smart　water　distribution　system　to　show　the　feasibility.