Main breaks 101 – Raising our infrastructure GPA

A meain break at Sheridan Boulevard and Fifth Avenue in July 2013 stopped traffic. Denver Water spent more than $2 million on main breaks and leaks last year.

A main break at Sheridan Boulevard and Fifth Avenue in July 2013 stopped traffic.

The American Society of Civil Engineers’ 2013 grade for America’s drinking water infrastructure was a D, which is no surprise considering there are 240,000 water main breaks each year in the U.S.

With a significant portion of our system installed right after World War II, Denver Water is no stranger to main breaks and leaks. Not only does this mean disruption to our customers, it also means we’re losing our most precious resource – water.

But, we’re working hard to limit these issues and help raise the GPA of the nation’s water infrastructure.

Check out the curriculum for Main Breaks 101:

Home Room – The basics.

Denver Water operates and maintains more than 3,000 miles of pipe – enough to stretch from L.A. to New York. The treated water distribution pipes in our system vary in size, from ½-inch diameter service lines to a 108-inch diameter conduit.

Cracks and breaks occur based on the condition of the water main and its surroundings. Because many factors can contribute to a water main breaking or leaking – including age, pipe material, how corrosive the soil is, water flow, temperature and more – many times we are unable to identify one cause of the problem.

While every main break is different, fixing it quickly is our number one priority – to minimize disruption to our customers who live, work or commute in the area, and to make sure we lose as little water as possible.

A Denver Water crew digs to locate a main break at Lincoln Street and Fifth Avenue in December 2013.

A Denver Water crew digs to locate a main break at Lincoln Street and Fifth Avenue in December 2013.

Accounting – Water lost.

As part of running a water system, every water utility experiences water loss, which is called non-revenue water because we treat it, but it doesn’t get billed to customers. Most of this water is essential to running a water system and maintaining the health and safety of the public – water that goes to firefighting, water quality sampling and flushing, and draining for annual system maintenance and construction, for example. In 2013, our non-revenue water was about 3.5 percent of our total treated water.

We work hard to keep our non-revenue water to a minimum, but unfortunately, water loss due to undetected leakage in the system still occurs. In 2013, we estimate that amount was less than 2 percent of our total treated water. Our goal is to proactively detect non-surfacing leaks and respond quickly to water main breaks across our system, and we estimate that less than 1 percent of the water we treat annually is lost when we find and repair these problems.

When you treat more than 60 billion gallons of water a year, however, the percentage of water lost to main breaks and leaks add up, which is why we have numerous programs in place to proactively identify and minimize leaks, and upgrade and repair our aging system.

Math – Calculating water lost.

How do we know how much water is lost through main breaks and leaks? Without a water meter attached to a main break – which isn’t a viable option – we have to rely on calculations that factor in the size of the pipe, cause of the break (corrosion, temperature, etc.), average flow rates and average water shut-off times. The majority of our repairs are on ¾-inch-diameter service lines and pipes that are between 6 and 16 inches in diameter. Here’s how some of the numbers break down:

  • ¾-inch service line leak = 15,000 gallons lost
  • 6-inch main break = 30,000-156,000 gallons lost
  • 8-inch main break = 35,000-252,000 gallons lost
  • 12-inch main break = 45,000-378,000 gallons lost
  • 16-inch main break = 52,000-1,125,000 gallons lost

Applied Science – What we’re doing about it.

We have proactive programs in place to identify and  minimize the water loss in our system, such as:

  • Leak detection – We’ve saved an estimated 138 million gallons of water over the past 5 years through this program.
  • Pipe rehabilitation and pipe replacement – We install, replace or rehabilitate about 20 miles of new pipe a year – pipes we’ve identified with high potential to break or pipes that can be relined, which helps extend the life of the pipe.PowerPoint Presentation
  • Pressure regulating valve maintenance and replacement – A new program launched in 2012, which allows us to replace or repair the valves that regulate the 160 pressure zones in our system, reducing the number of main breaks caused by these valves.
  • Corrosion control – We have more than 4,000 test sites on pipes throughout our system to help us calculate the rates of corrosion and decide which pipes need to be replaced before they cause major damage.

Homework – How can you help?

You already do! Your water rates fund the programs to maintain, upgrade and replace our aging system, helping us ensure we provide you and the 1.3 million people we serve with clean, safe water every day.

If you see what may appear to be a leak in the street, call us at 303-628-6801.

And be sure to visit our website to learn how to troubleshoot problems and fix leaks at your home or business.

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