KHAN BANI SAAD, Iraq – A $40 million prison sits in the desert north of Baghdad, empty. A $165 million children\’s hospital goes unused in the south. A $100 million waste water treatment system in Fallujah has cost three times more than projected, yet sewage still runs through the streets.

As the U.S. draws down in Iraq, it is leaving behind hundreds of abandoned or incomplete projects. More than $5 billion in American taxpayer funds has been wasted — more than 10 percent of the some $50 billion the U.S. has spent on reconstruction in Iraq, according to audits from a U.S. watchdog agency.

That amount is likely an underestimate, based on an analysis of more than 300 reports by auditors with the special inspector general for Iraq reconstruction. And it does not take into account security costs, which have run almost 17 percent for some projects.