The toilets on the Navy's newest aircraft carriers clog frequently, and it costs $400,000 a flush to fix them, according to a new government watchdog report.

During a review of Navy shipbuilding programs by the Government Accountability Office, 150 systemic maintenance problems were identified.

"These problems resulted in more effort and cost for the fleet in sustainment than expected," the GAO said.

One problem mentioned in the report was clogged toilets.

The Navy installed new toilet and sewage systems — ones similar to those on a commercial aircraft but scaled up to support a large crew of more than 4,000 people — on the Nimitz-class aircraft carrier USS George H.W. Bush (CVN-77) and the newer, first-in-class USS Gerald R. Ford (CVN-78).

These systems reportedly cannot withstand demand without having problems.

"To address unexpected and frequent clogging of the system, the Navy has determined that it needs to acid flush the CVN 77 and 78's sewage system on a regular basis," the GAO found.

Each acid flush costs $400,000, the GAO revealed, citing fleet maintenance officials.

The report explained that the acid flushes are "an unplanned maintenance action for the entire service life of the ship," and it is difficult to calculate sustainment costs given that it is unclear exactly how many times this process will need to be repeated.

Bloomberg News was the first to notice the Navy's costly clogged toilets, which illustrate how ships being delivered can end up costing more to sustain than was anticipated.

"The Navy has delivered warships—such as aircraft carriers, destroyers, and submarines—to its fleet over the past 10 years that require more effort to sustain than initially planned," the GAO said, revealing that it has assessed that the Navy initially underestimated sustainment costs for a handful of shipbuilding programs by $130 billion.

The watchdog noted that while the toilet issue was an excellent example of the problem the Navy faces, "we generally did not include these types of ongoing costs in our calculation."

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