Experiments were run in the pipe loop setup toestimate bulk and wall chlorine decay rates undervarying flow and chlorine levels for groundwater. Arecirculating loop of 50 mm inner diameter polyvinylchloride pipe and a variable flow pump with feed andrecirculation tank were used to design a pipe loop.Sodium hypochlorite was introduced as free chlorineinto the test water. The study came up with three importantfindings: (a) bulk chlorine decay rate in testwater decreased with increase in chlorine levels, whichis attributed to the type and level of organic matterpresent in test water. (b) Chlorine decay rate inpilot loop setup increased with increase in flowvelocity. The result showed that under turbulent conditions,in addition to chlorine, mass flux transferfrom bulk to wall and biofilm removal from pipe surfacecontributed to chlorine decay. We also noted thatwith increase in flow velocity the contribution of bulkreaction to total chlorine decay in pipe loop decreased.(c) ANOVA test on experimental dataset showed thatas compared to initial chlorine levels, flow velocity hasstatistically significant effect on chlorine dissipation ina pipe loop. We also found that after turbulent flow isachieved, the effect of flow velocity on the wall decayis negligible.