The Navy is placing a $10 million order for work to replace a 24-inch underwater waterline crossing Pearl Harbor.

The project is part of a larger Navy effort to upgrade deteriorating cast iron waterlines and replace them with plastic pipes.

The work will replace about 3,800 linear feet of pipe from Pearl City Peninsula to Ford Island. About two-thirds of the existing line is underwater.

Naval Facilities Engineering Command Pacific said Friday the work is expected to be finished by April 2015.

The Navy awarded the order to Watts-Healy Tibbitts, a joint venture company.