Have you ever seen a Texas Water Company (TWC) employee open a hydrant or pipe to let water out? They were performing a flushing operation.
Water flushing is a routine maintenance activity that water utilities perform to remove particles from water infrastructure. This article explains how flushing is performed, the parameters technicians follow, Texas regulations, and specialized types of flushing.
Even when water is safe to drink, it contains minerals and particles that slowly build up in water mains. To prevent excessive accumulation and improve the water’s appearance and taste, these particles are removed at strategic flushing points throughout the distribution system.
Regular flushing helps keep the water system in good condition and allows water to flow through clean pipes without obstruction.
Flushing also provides important information about water pressure and hydrant maintenance. When flushing is performed through fire hydrants, technicians can measure the pressure in the water main and assess whether the hydrant is operating effectively.
Lastly, flushing is essential for eliminating stagnant water from pipes and preserving water quality. Especially during warmer months, disinfectant levels in the water may decline more quickly. Flushing helps restore the disinfectant residual by bringing fresh water into the mains.
Together, these benefits make flushing an essential part of maintaining a reliable water system and protecting water quality.
Each time a water main is flushed, our technicians test the chlorine residual level to ensure water quality standards are maintained throughout the distribution system.
The results help technicians monitor water quality during the flushing process and determine whether enough disinfectant is present. Maintaining the appropriate chlorine residual helps preserve water quality as water moves through the distribution system to homes and businesses. Depending on the chlorine residual level and the location of the flushing point, flushing can last from a few minutes to 20 minutes or more. The operation concludes only after test results fall within standard parameters.
In Texas, flushing is regulated by the Texas Commission on Environmental Quality (TCEQ), which establishes testing requirements and disinfectant parameters.
Flushing is an important part of system maintenance and water quality protection and must be performed regardless of drought conditions. Utilities must account for the water used for flushing in drought planning and water-capacity calculations. Each year, they must also report to TCEQ the exact amount of water used during flushing operations and include that information in the annual Consumer Confidence Report (CCR).
Learn more about the purpose of flushing.
In some TWC service areas, automated flushing points are designed to release and test water at scheduled intervals. These devices help maintain water quality in areas where water may remain in the distribution system longer, such as dead-end mains or locations with lower demand. Because these flushing events are intentional and part of normal system operations, seeing water flowing from one of these devices does not necessarily indicate a problem with the hydrant, water main, or distribution system.
TWC staff routinely monitor the units, review water-quality results, and adjust flushing schedules as system conditions change.
Periodically, TWC performs a specialized type of flushing called scour flushing. This maintenance operation uses high-velocity, high-pressure water to clean the distribution system by loosening and removing built-up mineral deposits.
Unlike routine flushing, scour flushing is conducted as needed but is common for a single flush even to show benefits for years. It is performed by closing specific valves within the mains and directing the water toward designated exit points. The unidirectional flow increases the water’s velocity and pressure, enhancing its cleaning action.
Flushing helps ensure that the water delivered to your home or business continues to meet water-quality standards and that the distribution system remains reliable. It also supports proper water pressure, keeps fire hydrants operational, and helps prevent mineral buildup from affecting the appearance or taste of your water.
While flushing is underway, you may briefly notice a decrease in water pressure or discolored water caused by disturbed minerals in the pipes. These effects are typically temporary. Although seeing water released from the system may seem wasteful, flushing is a carefully managed maintenance practice that protects water quality and helps keep the system working as intended.
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