Have you ever gone out for a mid-morning walk or drive in your neighborhood only to find water flowing out of a fire hydrant with the familiar H2O truck nearby? This can be a concerning sight for many as it appears significant amounts of water are flowing straight into the storm sewer unused and wasted. You may be surprised to learn this process, called flushing, is an integral part of water systems routine preventative maintenance required by the Texas Commission on Environmental Quality (TCEQ). This flushing maintains the integrity of the water system and allows us to continue delivery of the highest quality water possible to our customers.

What is flushing?

Flushing is a process that rapidly removes water from the District’s water piping system, similar to the process of flushing a car’s radiator. Flushing uses water force to scour out materials that accumulate in the District’s pipes. Water pipes are usually flushed by opening fire hydrants, where the discharged water flows off the streets the same as rainwater.

Why are we flushing?

Imagine driving down the road at less than 1-1/2 miles per hour. That’s about the rate that water moves through underground pipes. This slow movement causes sediment like rust and mineral particles to build up over time and accumulate along the pipe’s bottom. A build-up of bacteria known as “biofilm” can also coat the pipe’s inner surface. This combination of sediment and bacteria can restrict water flow in the pipes. Also, some areas of the water distribution system have dead ends or low flow segments where water remains in the pipe longer and may slightly reduce the chlorine disinfectant levels in the water. Periodic flushing of the water system removes the sediments from the lines and refreshes the water in the dead end, low flow segments of the system.

Isn’t flushing a waste of water?

No. Any overall increase in the amount of water used in flushing is a small price to pay in maintaining water quality and the integrity of the piping system.

How will this affect you?

Usually, you will not be aware that flushing is even taking place in your neighborhood. Flushing is generally conducted between 8 a.m. and 4 p.m. Monday through Friday. It takes about 30 minutes to flush each hydrant. While the hydrant is being flushed, the homes on that block may experience slight drop in water pressure. Your water service should not be interrupted. The only sign that flushing has occurred in your neighborhood may be standing water in the roadway.