As we all know potable water is a vital commodity which should be justifiably conserved. All regulatory agencies, such as DEP, DOH, and SJRWMD place restrictions on potable water for varying purposes and protections. Potable water flushing from fire hydrants is not inherent to the U.C., it is an integral part of maintaining water quality and protection of the public in all water systems. Routine system flushing is absolutely necessary with a chloramine residual. Distribution systems have piping designed for fire capacity and with current conservation levels by consumers, flushing makes up the difference to keep water meeting disinfectant residuals within potable water standards.
Water mains are flushed to allow freshly treated water to move through the pipes to meet the standards for active disinfectant in the water at the time of sampling. [and flush out any sediments and reduce turbidity]. If possible, the water is flushed into grassy areas. Flushing is a requirement for circulation in the extremities of a service area, to maintain mandatory chlorine residual in any low usage areas and ensures compliance with operating permits. Regulatory test sample thresholds are increasingly becoming narrower and operationally more difficult to meet. Bottom Line – After leaving the plant the water must be used within an exact amount of time before the disinfectant (an oxidant) loses its capability to do its job. Flushing is our means to accomplish this when water use by customers is insufficient. In some places you’ll see a small yellow box on the side of the hydrants equipped with timed release, automated flushing device. In other places you notice our water quality, field technicians manually operating hydrants for the same purpose.
Potable water treatment processes at the U.C. are continually being evaluated and system modifications performed to diminish flushing volumes and enhance the chloramine performance in our distribution system. Examples of best practices for this purpose are detection and repair of leaking pipes, eliminations of redundant piping [situations], installation of chlorine booster pumps if needed, as well as periodic comprehensive free chlorine treatments of our system. Realized by-products of a well maintained water distribution system, beyond health, safety, and ultimately conservation of our drinking water, are also hydraulic capacity improvements and reductions in the re-growth of biofilm and disinfection demand, which correlates into performance improvements and reduced operating costs.