Improved Water Main Flushing to Use Less Water

Enabled by new, sophisticated computer software, Redding Water Utility crews will begin systematically flushing water mains in selected Enterprise and Cascade (South Redding) neighborhoods in early December.

The goal is to ensure the best possible water for customers by scouring mineral sediments from pipes that deliver water from nine wells in the two areas of the City. The minerals, most commonly iron and manganese, can accumulate in water mains during times of low usage but emerge when water use increases in the springtime.

Using a sophisticated computer modeling program, City staff for the first time will practice “unidirectional flushing.” This entails isolating specific water mains down to the residential block level and forcing high flows in one direction to flush sediment out through one or more fire hydrants. By comparison, “conventional flushing” done in past years encompassed larger areas with a much greater amount of water distributed out through multiple hydrants. The result is generally less-effective sediment removal and a greater loss of water.

While not a health risk at normal concentrations, the flushing operations can re-suspend accumulated mineral sediments. During those operations, it is important that residents refrain from washing clothes if their water appears discolored because the sediments can cause staining. Discolored water is certainly not appealing to drink, and city staff recommends that residents experiencing discolored water during flushing operations wait for the water to clear before using it for drinking or cooking.

Because of the ongoing drought this past summer, wholesale flushing of the Enterprise area was not done in order to conserve water. Selective flushing did occur in specific areas when levels of mineral sediment was especially noticeable.

Because it is area-focused and done with high velocity, the unidirectional flushing to be done in December will utilize significantly less water and be more effective. It also should result in much shorter disruptions to customers than in prior years.

Signs will be placed on streets scheduled for flushing to notify residents of upcoming work. The overall flushing operation will involve seven separate zones within the Enterprise / Cascade area. The first zone to be systematically flushed is a rectangular area bordered roughly by Rancho Road, Alta Mesa Drive, Castlewood Drive and Goodwater Avenue. Flushing operations in this first zone will begin Tuesday, December 2nd and finishing Thursday December 4th. Water crews will be working in this area all day, each of these three days. Residents in this zone are asked to curtail water usage as much as possible as household water could be discolored for a short period of time. Residents should specifically avoid washing clothes as sediment emerging from faucets could stain clothes.

A Flushing Hotline at 646-3745 has been set up for customers to check specific dates for their Enterprise or Cascade-area neighborhood. For additional information, contact John Wendele, Water Utility Manager, at 224-6068.

Note: Videos depicting unidirectional flushing and the software used are available here:

-from press release

Press Release

-from press release