Thousands of New Yorkers faced a major glitch in their commutes last week when a water main break spewed water everywhere – including 500,000 gallons into the underground subway system, the NY Times reported. Flooding above ground included water lapping at the steps of Lincoln Center. The reason for the break isn’t yet clear, but New York City’s water infrastructure is some of the oldest in the world. Some 6,800 miles of water mains send more than a billion gallons of water a day to NYC residents and businesses. An average of 474 water main breaks a year have been reported in the past five years.

Worldwide, cities and countries face difficult financial decisions as infrastructures age and water supplies are put at risk.

Just south of Los Angeles last week, for example, seven miles of coastline were closed in Long Beach after 11,000 gallons of sewage spilled into the San Gabriel River, which flows south to the Pacific Ocean, the LA Times reported. It turns out a grease blockage in a sewer line in the city of Hawaiian Gardens caused the massive spill and the resulting closure of coastal swimming areas. Beaches were expected to remain closed for at least a few days until water samples show that bacteria levels have decreased.

In August, also just south of LA, a spill of 50,000 gallons of sewage closed Huntington Harbor after a main sewer line blockage probably was caused by tree branches or roots.

Across the Pacific in Japan, one of the world’s most comprehensive water systems also is aging. The country’s 1,263 water companies, some serving fewer than 5,000 customers, are struggling with how to pay for maintenance and upgrades because of decreased income due to a shrinking population and an increase in water-saving appliances and technology, according to Japan’s rapid population drop is expected to go from the peak of 128 million in 2008 to 90 million by 2063 and 60 million by the year 2100. The country often faces natural disasters, though, including earthquakes and typhoons, making the quality of water and other infrastructure quite critical.

As we saw in New York last week, it’s a problem that can’t be ignored.