Why is all that water pouring into the street?

Flushing stagnant water out of our hydrants, all in the name of high-quality H2O.

September 23, 2016 | By: Steve Snyder

Steve Lovato gets the same question all the time.

“Why are you wasting water, especially if we’re in a drought?”

As a system quality supervisor for Denver Water, Lovato is charged with flushing more than 3,000 hydrants and blow-off valves in our distribution system. That means he opens hydrants all around the metro area — letting lots of water rush out onto the streets.


“These hydrants sit at the end of a water main, so water isn’t constantly circulating like in other parts of the system,” said Lovato. “When water sits in a pipe too long, the quality isn’t as high as when it leaves our treatment plants. Flushing the hydrants brings that water quality back to where we want it.”

So every year from April to October, Lovato and his team open hydrants to get rid of stagnant water, but not without a lot of preparation first.

“We look at the size and length of the water mains before we go out, so we have a good idea of how much water it will take to flush a particular area,” Lovato said.

On average, about 1,000 gallons of water is flushed before the water is back to Denver Water standards. That amount represents a very, very small amount of our total annual consumption — about 0.01 percent.

But as you can imagine, opening hydrants in a busy area tends to draw a crowd, so the crews put up signs and hand out informational pamphlets explaining what Denver Water is doing and why.

And boy, do people love to watch.

“We have kids come up to play in the water,” Lovato said. “We have people who fill buckets to put on their gardens and lawns.”

And yes, people ask him why we’re “wasting” so much water.

“They have a lot of questions, but when we tell them we are making sure they have high-quality water, they are very accepting of what we are doing,” Lovato added.

As the hydrants spew water, Lovato watches for clarity, while testing the temperature and water-quality levels. When everything meets Denver Water’s standards, Lovato seals the hydrant and moves on to the next stop. Each hydrant takes about 10 to 15 minutes to flush. But the impact is more lasting.

“It’s important to make sure people have great quality water,” Lovato said. “That’s the thing I love about my job.”

2 thoughts on “Why is all that water pouring into the street?”

  1. Why does it matter if the water coming from fire hydrants is high quality. It is just going on fires. Does that stagnant water in the ends of water mains somehow feedback into and contaminate water flowing on to consumers?

    1. Great clarifying question, Cody.

      The purpose of our flushing program is to flush the stagnant water from our water mains, not the hydrants. Essentially, our system is all connected. Our water mains are pipes that run underneath the street and are used to distribute water to homes (through service lines) and hydrants on each block. We use fire hydrants to purge stagnant water out of water mains that lead to dead-end streets, cul-de-sacs and pressure zone boundaries. At times, we also may flush hydrants upon request by fire departments to ensure adequate flow.

      Many don’t realize this, but Denver Water provides more than drinking water — our system is actually designed with fire protection in mind. You can learn more about our role in fire protection in, “Battling a blaze, at thousands of gallons per minute.”

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