IS THERE something in the water? City workers were mopping up Wednesday after the city's third water-main break in 10 days. Early in the morning, a nearly 100-year-old main burst, flooding the area around Front and Tioga streets in North Philadelphia.

Millions of gallons of water have poured into the streets because of main breaks in recent days. Crews are still cleaning up from a massive main break that occurred 11 days ago at 21st and Bainbridge streets in Southwest Center City.

A smaller break in the Northeast, at Willits Street and Ashton Road, occurred on Sunday and has been fixed.

So is this a big surge in breaks in the city's extensive network of steel pipes and water mains? Despite the recent leaks, officials say main breaks have not picked up in pace.

There were 965 breaks between July 1, 2010, and June 30, 2011, and just 531 between July 1, 2011, and June 30, 2012, said Debra McCarty, the Water Department's deputy commissioner for operations. And the city is well below the national average for main breaks.

Still, Philadelphia has an old water system. According to McCarty, the 3,100 miles of pipe in the city have an average age of 67 years.

The main that broke Wednesday dates back to 1906. She also noted that the system is put under additional stress during extreme weather, like the recent heat.

"Higher uses in the summer causes additional stress on the piping. It has been a hot summer. It could be a result of that," said McCarty, who said the cause for Wednesday's break was still unknown. "We have water-main breaks every day of the year."

Mayor Nutter recently called on the federal government to better fund city infrastructure projects, like shoring up the city's water system.

The city spends about $50 million a year to replace pipes and replaced 68.6 miles of pipe between 2006 and 2011, according to McCarty. She said that the city is working as aggressively as possible with the money available and noted that the city's pipe-replacement rate is faster than the national average.

But McCarty said that the city could replace pipes more quickly, at less cost to local taxpayers, with more state or federal aid.

The city plans to raise water rates 28.5 percent over the next four years, starting in October, in part to cover the costs of supporting the aging system.

"If there was more money available, that would help; we're doing with what we have," McCarty said.