About Hydrant Flushing
Chances are that at some point, you have noticed fire hydrants being flushed and releasing large amounts of water into the streets. While it may appear that hundreds of gallons are going to waste, there are actually several benefits to this hydrant flushing process. Water main flushing is an important preventative maintenance activity that:
- verifies proper operation of the hydrant
- evaluates the available flow to the hydrant
- removes mineral and sediment build up from the water mains
- allows utilities to deliver the highest quality water possible to their customers
Proper Operation of the Hydrant
The process of water main flushing is one of the most critical practices carried out by public drinking water systems. This practice allows water operators to identify broken or inoperable valves and hydrants to assure that they are working at their maximum potential.
Fire & Emergency Needs
During the flushing of a hydrant, operators can assess the water pressure and available flow rate for firefighting purposes. It’s imperative that each hydrant is operating as firefighters rely on them for fire-ground operations.
Mineral and Sediment Build Up
Throughout the course of several months or a year, loose sediment and mineral deposits may slowly build up inside of the water mains resulting in discolored water and reduced capacity. Flushing the water mains can remove the sediment and mineral build up, and improve the color, odor and taste of the water if it has been problematic. Unidirectional flushing at the minimum required velocity will improve the carrying capacity of the mains.
Over time, water settles, ages, and is affected by biofilm (a thin layer of microorganisms) that grows on the inside of the distribution piping. Each of these factors affects the quality and taste of the water, so it is important to flush the water out of the mains and hydrants regularly. Flushing can remove water from areas of the distribution system that have low water use, since the older water may no longer have the desired chorine residual.
Smell something different when turning on tap? That is the “smell of safety”!
Each spring, Spotsylvania County and the City of Fredericksburg will stop adding ammonia during the water treatment disinfection process for about one month. This annual change is temporary. It is done to ensure a high level of disinfection in water mains and pipes. During this process change, you may notice a change in the taste or odor of your tap water. View annual public notice HERE.
In order to draw this extra purification throughout the entire system, hydrants are then systematically flushed. While water is always under pressure in the pipes, this creates an increased demand and moves water through zones where the pressure may be lower, such as an end of the waterline. It will take roughly 2 months to circulate through the entire water system. You will usually smell the difference as it passes your house, not the entire program period.
What can I do to prepare for flushing?