Abstract Submission: Water quality impacts public health and can degrade due to a range of factors including, stagnation, corrosion, loss of disinfectant, formation of disinfection byproducts, growth of microorganisms (e.g., Legionella), or potential contamination after a chemical spill. Flushing is a common tool for restoring water quality both at the water distribution network and premise plumbing scales. However, premise plumbing flushing procedures vary widely in their details, including total flowrate, duration, number of concurrent fixtures flushed, and order of steps. These procedures are followed by the homeowner and lack of clarity in procedures may lead to non-ideal outcomes. Four procedures from utilities and peer-reviewed journals were performed experimentally using a model home plumbing system contaminated with a nonreactive salt tracer. Additional experiments targeted specific flushing of the hot water heater and toilet. Experimental results highlighted the central role of the hot water heater in system flushing, and confirmed the increased time and water used to fully replace its volume. Some procedures did not flush for a sufficient time to fully remove the tracer, which was worsened at lower system pressures that produced less flow. Formulas were developed to predict the concentration reduction associated with toilet flushing in the toilet’s tank and bowl. Experimental results were compared to EPANET-MSX 2.0 models developed from flow data collected during the study. This presentation will discuss these experiments and their results along with the value of EPANET-MSX in future flushing studies.
