Shock chlorination and remedial flushing are suggested to addressLegionella pneumophila(Lp) contamination in buildings or during their (re)commissioning. However, data on general microbial measurements (adenosine tri-phosphate [ATP], total cell counts [TCC]), and the abundance ofLpare lacking to support their temporary implementation with variable water demands. In this study, the weekly short-term (3-week) impact of shock chlorination (20–25 mg/L free chlorine, 16 h) or remedial flushing (5-min flush) combined with distinct flushing regimes (daily, weekly, stagnant) was investigated in duplicates of showerheads in two shower systems. Results showed that the combination of stagnation and shock chlorination prompted biomass regrowth, with ATP and TCC in the first draws reaching large regrowth factors of 4.31–7.07-fold and 3.51–5.68-fold, respectively, from baseline values. Contrastingly, remedial flushing followed by stagnation generally resulted in complete or larger regrowth inLpculturability and gene copies (gc). Irrespective of the intervention, daily flushed showerheads resulted in significantly (p< 0.05) lower ATP and TCC, as well as lowerLpconcentrations than weekly flushes, in general. Nonetheless,Lppersisted at concentrations ranging from 11 to 223 as the most probable number per liter (MPN/L) and in the same order of magnitude (103–104gc/L) than baseline values after remedial flushing, despite daily/weekly flushing, unlike shock chlorination which suppressedLpculturability (down 3-log) for two weeks and gene copies by 1-log. This study provides insights on the most optimal short-term combination of remedial and preventative strategies that can be considered pending the implementation of suitable engineering controls or building-wide treatment.