Another important step in transitioning Waukesha’s system from groundwater to Lake Michigan water will begin in September, with flushing or “scouring” select local water mains to fully prepare them for the water supply conversion.

“This flushing process is a normal practice in all water systems, including ours, to remove sediment that has accumulated in water pipelines over time,” said Kelly Zylstra, Operations Manager for the Waukesha Water Utility. “But to prepare for this historic water supply conversion, we’re launching a strategic and targeted additional program now, so that our system will be well-prepared for the new water supply.”

The flushing process, known as “Unidirectional Flushing,” essentially forces large volumes of water at high speed through pipelines. Flushed water is then released into the storm drains. Jacobs Engineering, the City’s consulting engineer for this effort, will begin flushing in select zones within the City and will then sequentially broaden the effort, cleaning the pipelines while also monitoring water flow, velocity, and pressure.

In all cases, neighboring residents and businesses will be notified of the location and timing of the flushing, along with steps they can take to prepare for it. Properties in flushing zones can sometimes experience temporary pressure reductions, in addition to occasional discolored water.
“While we know flushing can create temporary disruptions for our customers, this is a critical step toward ensuring a high quality, reliable Lake Michigan water source for our community and we are very excited to move even closer to that goal,” said Zylstra.

Pipeline Flushing - infographic