We strive to maintain water service for customers during the program; however, unforeseen conditions can occur that require water to be shut off for a short period. If you lose water service while the flushing operation is occurring in your area, it is a good idea to contact Water Utilities. Your report will allow our field technicians to investigate if the water loss you’re experiencing is a known issue or an unknown issue.

Flushing helps maintain water quality. The water entering distribution mains is of very high quality; however, water can deteriorate in distribution mains if the mains are not properly managed and unidirectional flushing is a technique for managing a water distribution system.

The City of Longmont water distribution system is a complex network of pipes and storage reservoirs where sediment or deposits may naturally accumulate over time. The flushing program removes sediment and ensures that the distribution system is operating correctly.

The City of Longmont has a network of storm drainage pipes, ditches, and drainage basins that directs water to various detention ponds, creeks, ponds, and rivers. The water utilized during the flushing program also uses these pipelines and drainage ways. This allows water to get re-used in various ways, whether it goes to a local farmer through an irrigation ditch or into a river for re-use downstream. Local lakes like McIntosh Lake and Union Reservoir can be fed in some ways by these networks of pipes. Additionally, the City of Longmont accounts for this type of water usage through the Water Resources Division.

The amount of water used to flush a particular section of pipe depends on a lot of factors, such as water main size and system pressure. A typical residential fire hydrant can flow on average between 1500 – 2000 gallons per minute. Flushing uses on average .005% (1/2 of 1%) of the drinking water that the City of Longmont uses on a yearly basis.

Each year, information is published in City Line, the monthly newsletter included with all City of Longmont utility bills, on our City of Longmont social media accounts, and to the Flushing web page. All sources will refer residents to the Water Flushing map to show the date(s) that we will be flushing the water supply system that services your home. It is always possible that these dates can change if we run into any unanticipated problems during the program. However, we strive to stick with our published schedule.

Normally, flushing takes place for approximately a 3-week period during early spring. You can see when crews will be in your neighborhood by visiting the interactive web map located on the Water Line Flushing web page. Water crews only flush lines Monday- Friday between the hours of 7:00 a.m. – 4:00 p.m.

If the cold water is clear, then the water is okay. If you encounter discolored water, shut the water off and wait several minutes. After waiting, check the clarity by running cold water for a few minutes allowing new water to work its way into your pipes. If not, wait a few more minutes and check again. This discoloration only affects the appearance of the water; it does not affect the taste or water quality.

The water system feeds both your cold and hot water system in a typical home. If you happen to use hot water during flushing, it may be necessary to drain your hot water tank. If this happens, stop using water immediately, and wait until crews are out of the area to continue hot water use.

When buildings are unoccupied for extended periods of time and water is not being regularly used, the water can sit and become stagnant. When this happens, such as during business shutdowns related to COVID-19, water quality may degrade over time.

Three different crews are assigned to flush water lines. These crews travel across the city very quickly in order to complete all flushing within a month. Due to the large number of customers affected, we are not able to use door tags to notify residents when when we will be in their areas.

However, residents can find anticipated flushing dates in a variety of places. Each year, information is published in City Line, the monthly newsletter included with all City of Longmont utility bills, on the City of Longmont social media accounts, and to the Flushing web page. All sources will refer residents to the Water Flushing map to show the date(s) that we will be flushing the water supply system that services your home. It is always possible that these dates can change if we run into any unanticipated problems during the program. However, we strive to stick with our published schedule.