The New Orleans Sewerage & Water Board may have to find another candidate to serve as its next executive director — another headache for an agency that also is in the midst of replacing most of its board members and undertaking hundreds of millions of dollars in upgrades to the city’s aging water and sewer infrastructure.

Last year, the board offered the job to Mayor Mitch Landrieu’s deputy mayor for facilities and infrastructure, Cedric Grant. But before negotiating a contract, the board decided to get an opinion from the Louisiana Board of Ethics on whether Grant could make the jump from the Mayor’s Office without violating any rules.

While the Ethics Board won’t make a formal ruling until a meeting scheduled for Friday, the board’s staff has issued a draft opinion saying Grant should have to wait two years before taking the post.

The draft opinion cites a state law that prohibits individuals from serving on a public board, stepping down and then seeking a job or contract with that board within a two-year period.

That rule could trip up Grant’s appointment because, although not an official member of the agency’s board of directors, he has often served as Landrieu’s stand-in at meetings of the Sewerage & Water Board, where the mayor automatically serves as board president. The opinion notes that Grant attended 27 of 31 board meetings over the past three years.

The Ethics Board is scheduled to vote on whether to accept the staff’s opinion during its April meeting Friday in Baton Rouge.

If Grant cannot accept the position, the next likely candidate would appear to be Tracie Boutte, a vice president with Entergy Services Inc. The Sewerage & Water Board named her as its No. 2 choice in December, in case contract negotiations with Grant didn’t pan out.

Whoever takes the job likely will be among the best-compensated officials in city government — Marcia St. Martin, the executive director since 2004, earns more than $200,000 a year — and will have a big task ahead.

City officials say New Orleans has been putting off much-needed repairs for decades, and the flooding after Hurricane Katrina made matters worse. Since then, officials have had to periodically warn residents to boil their tap water because of the potential for bacterial contamination of the system after any significant drop in water pressure.

Money from a recent hike in water rates and federal aid is earmarked to finance major improvements over the next few years.