Flushing hydrants can be a source of nuisance for people who live in places with low water supplies or who pay high premiums so that their taps keep on flowing. You must have come across such a situation and would have thought, “What a waste of good clean water!” Although it appears to be a wastage of good clean water, flushing hydrants is important in order to keep your water safe and maintain the reliability of a pipe network. In addition to analysing the fire flow capacity in case of a fire, flushing hydrants can also be done to eliminate sediment and rust from the water, or to maintain proper chlorine concentrations in your area.
First of all, we will examine flushing hydrants as a source of maintaining chlorine concentrations high for disinfection purposes. The common disinfection processes used in US water treatment plants are chlorine additions which makes sure that bacteria are not flourishing in the water or pipe network. But, the natural degradation of chlorine occurs the longer it is in water which implies that if water stays in pipes for long or further away from the treatment plant, it can have lower concentrations than tolerable and therefore, creating danger. Hence, the purpose of flushing the hydrants is to keep water moving and keep pipes from decaying in such scenario.
In case water becomes immobile in pipes or it becomes polluted, hydrant flushing again turns out to be essential. Broken pipes and even the linings of the pipes themselves can lead to seepage of sediments, rust, and even chemicals into the water system. Engineers are familiar with this risk and hence find out key locations where hydrant flushing will assist in enhancing water quality.
Lastly, hydrants may also be flushed in order to examine or record flow rates. To maintain safety in the event of a disaster, certain codes are used which signify the necessary fire flows from hydrants. In case of a burst pipe or other usage of water by users, pressure and flow rates at hydrants can be extremely affected. It has been confirmed by periodical analysis that there is enough water supply that can affect home and business owners’ insurance rates as well.
In short, in case you happen to witness a fire hydrant running for hours continuously, it is not the city just wasting water. If the city could possibly keep water, it would. In any case, as nobody is paying for the water being flushed from a hydrant, therefore, the water utility loses some money in the long run. Now, the question would arise that if water is unsuitable for drinking then why not utilize it to water a park or put it to any other good use. Despite being a moral endeavour, it turns out to be very costly every so often, and hence dumping the excess down storm drains is the only feasible solution. In case you are interested to hear this straight from a water utility, take a look at the video below that describes why Plano, Texas, a suburb of Dallas, often need to flush their hydrants.
Here is another video on hydrant flushing: