Toilets, known as “heads” in naval circles, on two US Navy Aircraft Carriers are prone to blocking and cost $400,000 to clear with acid, a report from the Government Accountability Office (GAO) has found.

The toilet problems were one of several issues found in a report on navy shipbuilding that found 150 class-wide problems affecting maintenance costs. The GAO found that the US Navy and Department of Defence (DOD) had also underestimated the sustainment costs for six programmes by $130bn.

Operating and support cost growths:

  • San Antonio-class (LPD 17) (26), $24.6bn
  • Zumwalt-class (DDG 1000) (3), $3.5bn
  • America-class (LHA 6) (3), $9.5bn
  • Ford-class (CVN 78) (4), $45.8bn
  • Littoral Combat Ship (LCS) seaframes (35), $22.8bn
  • Virginia-class (SSN 774) (48), $24.2bn

One highlight of the report is toilet problems aboard the USS George H.W. Bush (CVN-77), and new USS Gerald R. Ford (CVN-78). The carriers use a sewage system similar to that installed on commercial airliners.

This system, however, is prone to blocking and requires an acid flush regularly to clear problems and blockages. Each acid flush is estimated to cost $400,000.

The GAO report said: “According to fleet maintenance officials, while each acid flush costs about $400,000, the Navy has yet to determine how often and for how many ships this action will need to be repeated, making the full cost impact difficult to quantify. We generally did not include these types of ongoing costs in our calculation.”

The GAO found that the current Operating and Support (O&S) cost estimate for the Ford-class aircraft carriers is $120bn, up $45.8bn from the original estimated O&S cost of $77.3bn. Overall the difference between current O&S costs, and the initial O&S costs found by the GAO is $130.2bn.

Ford’s O&S costs increased by the most of any of the shipbuilding programmes assessed by the GAO.