Philadelphia has had three water main breaks in the last two weeks, including a massive break that opened a huge hole at an intersection just a few blocks from the city's downtown business district. The most recent happened on Wednesday.
Utility officials say warmer water temperatures can cause pipes to expand. Coupled with increased water usage the pipes are under more stress.
The majority of pipe ruptures happen in the winter but water department officials say those are usually smaller lines. The warm-weather problems are an issue for larger pipes.