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Water Line Flushing

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Annual Water Main Line Flushing Program

Each spring, the City of Longmont water staff flushes the main water lines to keep water quality at its highest level and to ensure that fire hydrants are operational. The benefits realized in water quality and fire protection far outweigh the comparatively small amount of water released during the flushing program.

Residents may notice low water pressure, discolored water, or no water for short periods of time when flushing is taking place in their neighborhood. We recommend residents limit water use, and particularly avoid using hot water when flushing is occurring in their immediate area.

Find Frequently Asked Questions at the bottom of this page. For additional questions, please contact Water.

Know When We're Coming And When We're Finished

The PDF Schedule Map shows when we anticipate being in your neighborhood. The Interactive Web Map shows which areas we have completed and which we have yet to complete. View both maps here.

Note: All scheduling is provided as an estimate; changes may occur due to weather or other unforeseen circumstances.

Expand/Contract Questions and Answers

  • Will I lose water service during the flushing program?

  • Why does the City of Longmont flush water mains?

  • How does flushing improve water quality?

  • Where does the water go?

  • How much water is used to flush mains?

  • How do I know when my area will be flushed?

  • When does flushing normally occur?

  • What should I do if I use water while my water line is being flushed?

  • Why should I only use cold water when the crews are in my area?

  • My business has been closed and no one was using the water (sinks, fountains, flushing toilets). What do I need to do to safely flush old water before reopening?

  • Why wasn't I notified of water line flushing in my area?

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