Impact of advanced water conservation features and new copper pipe on rapid chloramine decay and microbial regrowth

Abstract

Taste and odor issues occurring in new buildings were attributed to rapid loss of chloramine residual, high levels of microbes in the potable water system, and high water age due to use of advanced water conservation devices. Laboratory experiments confirmed that chloramine could decay rapidly in the presence of new copper pipe, providing a possible explanation for the rapid disinfectant loss in the new buildings. Higher temperature and lower pH also accelerated the rate of chloramine decay in copper pipes. The reaction was slowed by the addition of phosphate inhibitor or aluminum, which presumably formed barriers between the pipe wall and the chloramine in the bulk water. Additional research is needed to better understand how to maintain high quality water in buildings while also conserving water.