System Flushing

System Flushing_1

Flushing hydrants is an important part of maintaining water quality throughout the year.

Flushing the hydrants is an important part of a routine maintenance program necessary to maintain the integrity of the water system and ensure high quality water is delivered to our customers. Flushing hydrants or dead-end water lines is a State of Texas requirement by the Texas Commission on Environmental Quality (TCEQ).

Water lines are flushed for these main reasons:

1. To maintain water quality
The disinfectant, chloramine, becomes less effective as water collects and becomes older. This process is exacerbated in warmer months as rising temperatures can accelerate the degradation of disinfection in the water.  Also, during fall and winter months when water demand is lower, chlorine dissipates in the pipe to the point where levels approach regulatory minimums. If tests indicate that water quality may be affected, the City often flushes water lines and dead-end mains so that fresher water with a higher level of disinfectant is present.  The Utilities Division monitors the disinfectant levels closely and takes over 50 samples a week from various locations within the City. When monitored chloramine levels approach regulatory minimums, Utilities staff flush water from fire hydrants to pull newer water with higher chlorine levels to maintain water quality. This is a routine and necessary regulatory requirement. Blue signs are placed near the open fire hydrant to notify the public that this flushing is for water quality purposes.

2. To clean water mains
Over time, small particles can build up inside the water distribution pipes and can have an impact of water quality.  Mesquite Utilities uses flushing to pull water at high velocity through pipes to a discharge point. The rapid flow of water scours the insides of the pipes.

3. To conduct fire flow tests
Fire hydrants are tested periodically to ensure and document proper functioning so they are ready for an emergency.

System Flushing does not impact the cost of water to Mesquite citizens.

The City pays the North Texas Municipal Water District for a set amount of water under the “take-or-pay” requirements. The annual City usage is far below the required amount we must pay NTMWD. The flushing activity does not add to our annual bill from the NTMWD and therefore has no effect on customer water bills.

System Flushing_2