Infographic: The Age of U.S. Drinking Water Pipes — From Civil War Era to Today

Water main ages reflect the nation’s growth

By Brett Walton
Circle of Blue

The American Water Works Association calls it the Replacement Era. An estimated 1.9 million kilometers (1.2 million miles) of distribution pipes supply Americans with drinking water. Many of them are nearing or have past retirement age. A big investment — perhaps as much as $US 1 trillion over the next two decades — must be made to replace them.

Age, however, is only part of the story. The deterioration of any particular pipe depends on a bundle of pressures: What material are the pipes made of? Cast iron, ductile iron, polyvinyl chloride, or, occasionally, wood? Each has a different lifespan. What are the chemical properties of the soil and water? Some are more corrosive. What is the climate? Cycles of freezing and thawing or drought can weaken pipes.

The need to replace these pipes, most of which have a useful lifespan of more than 75 or 100 years, will continue to grow. The U.S. Environmental Protection Agency forecasts that the rate of replacement will rise until 2035, as national investment in water mains peaked in the boom years after World War II.

The graphic below shows the percent of current water mains installed by decade. The patterns reflect America’s growth. Older pipes weave beneath the colonial cities on the East Coast. Philadelphia, for one, still uses water mains installed before the Civil War.

Cities that grew fast in the latter half of last century have newer systems. More than half of San Antonio’s water mains were laid in the ground between 1980 and 2010 — which seems appropriate given that its population grew by 70 percent in that period.


Graphic © Kaye LaFond / Circle of Blue
The percent of current water mains installed by decade for five U.S. cities. Click image to enlarge.
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  1. […] in the United States is aging rapidly. In 2017, the average age of most pipes in the country was around 47 years old. The situation is worse in in New York and Philadelphia, where the pipes are pushing 70. Therefore, […]

  2. […] Protection Agency find­ings issued in 2018 esti­mat­ed that water util­i­ties, which have over 1 million miles of buried pipe, need to invest $472 bil­lion for cap­i­tal improve­ments over two decades in […]

  3. […] is considered poor, very poor or elapsed. It is old, with portions installed prior to the Civil War, especially in older cities on the East Coast. An estimated 2.1 trillion gallons — or 6 billion […]

  4. […] However, the installation of these systems is so old in some parts of the country, that drinking what comes out of them is like drinking directly from the sewage. Read more on the subject in this great article here. […]

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