Biggest threat to U.S. drinking water? Rust

CHICAGO (Reuters) - From an attack by militants to a decline in snow melt caused by global warming, public fears about the water supply have heightened in the United States.

A resident holds up a bottle of silty water taken from a household tap in North Vancouver November 17, 2006. Health officials issued a boil-water advisory for the Vancouver-area after a storm stirred up silt in the region's reservoirs and increased the risk of bacteria-borne disease. More than 170,000 public water systems in the United States work to meet the standards of 1974's Safe Drinking Water Act, but experts say the iron pipes the cleaned water travels through before reaching homes let water out and diseases in as they corrode. REUTERS/Andy Clark

So who would have thought the top worry among water experts turns out to be rusty pipes?

“If you clean up water and then put it into a dirty pipe, there’s not much point,” said Timothy Ford, a microbiologist and water research scientist with Montana State University.

“I consider the distribution system to be the highest risk and the greatest problem we are going to be facing in the future,” Ford said.

Towns and cities across the United States spend more than $50 billion each year cleaning water sourced from rivers, lakes and underground aquifers.

More than 170,000 public water systems are at work to keep tap water flowing into American homes and meeting the standards of the Safe Drinking Water Act of 1974.

But after the extensive purifying process, water ends up in your glass after traveling through pipes laid under city streets 50, 60 or 100 years ago.

Those pipes -- made mostly from iron until plastic was introduced 30 years ago -- span almost one million miles in the United States.

As the iron pipes corrode and break, not only does water escape, but also diseases get in, experts say.

“Investigations conducted in the last five years suggest that a substantial proportion of waterborne disease outbreaks, both microbial and chemical, is attributable to problems within distribution systems,” the National Research Council said in a study for the Environmental Protection Agency released in December.

The amount of water lost is a sign the system is aging, experts say.

The oldest, largest cities in the country -- Philadelphia, Chicago, Denver, New York -- are all showing signs that their distribution systems are in need of repair, said Eric Goldstein, a spokesman for the Natural Resources Defense Council, a leading environmental group.

In New York City, for example, the biggest leak in its system loses 1 billion gallons of water a month, he said.

It’s that aging infrastructure that poses a rising health threat to consumers, experts say.

More than 273 million Americans get their water from a public distribution system. The other 10 percent of Americans source their water from private, unregulated wells.

Fears about tap water quality are sparking more Americans to turn to bottled water or home filtration systems.

More than 40 percent of American homes use some kind of water treatment product, according to NSF International, a not-for-profit public health and safety group.

EPA rules require that water leaving a city’s water plant be tested for microorganisms like cryptosporidium and legionella that thrive in degraded water systems.

EPA also requires tests for a slew of other contaminants, including lead, copper and arsenic, which can lead to any number of gastrointestinal or other illnesses.

But once water has been purged of such impurities, different ones can enter the water supply as it courses through miles of old pipe.

“We estimate in the next 20 to 30 years water utilities will have to invest $250 to $350 billion just to replace the pipes that are in the ground today,” said Jack Hoffbuhr, executive director of the American Water Works Association, the industry’s trade group.

The cost of improving U.S. water infrastructure may triple the cost of water by 2030, according to the association.

“We committed 100 years ago to build a reliable, low-cost, high-quality municipal drinking water systems. But there are no guarantees that will continue,” said Peter Gleick, president of the Pacific Institute, a research group in Oakland, California.