Flint knows it has a problem with water leaks. It just doesn't know how many, or where, the leaks are.
Spokesman Jason Lorenz says the city may be losing up to 30% of its water from leaks.
"What with the age of the system being 50 to 100 years old in some places," says Lorenz, "and by nature of it being underground, there's just not a lot of ways to tell something's gone wrong until it reaches the surface."
The city hopes to change that.
For the next 10 to 14 weeks, a company called Echologics will be dropping sensors down manholes throughout the city and detecting leaks using acoustic waves.
The project is being paid for with a $900,000 Distressed Cities grant from the federal government.