New Orleans officials are making a last-minute push to get voters to support a drainage tax renewal and a new tax to cover the settlement of a decades-old dispute with the city's firefighters.

City officials and members of the business community held a news conference Wednesday to stump for the two tax propositions on Saturday's ballot.

Mayor Mitch Landrieu described the drainage tax as necessary to provide a “basic, fundamental” service that is needed to “keep the city safe and dry.”

The tax, which will expire at the end of the year unless renewed, is one of three that fund the Sewerage & Water Board's drainage operations, bringing in about $15.4 million of the $51.1 million a year it costs to keep the drainage system maintained and the pumps that push water out of the city running.

There’s no immediate plan for filling that shortfall without the tax. Asked what would happen if the tax fails, Landrieu said, “We’re going to get wet.”

The drainage tax is now assessed at 4.66 mills but would drop to 4.46 mills under the renewal. A homestead-exempt property worth $350,000 now pays about $128 a year because of the tax and would pay about $123 under the lower rate.

City officials have compared that cost to the savings on their insurance rates that many New Orleans property owners received when new flood maps went into effect this year, noting that the city’s drainage and flood protection systems played a role in the reduced rates.

“If the millage is not renewed, we’re going to have trouble keeping the pumps on,” Landrieu said.

The property tax increase for the Fire Department, which also is on the ballot Saturday, is the city’s second attempt to get voters to approve a new millage to pay for the settlement of a long-running legal dispute over $75 million in back pay owed to firefighters.

The 2.5-mill tax, which would bring in about $8.9 million a year, would last for 12 years. In each of those years, the city would use $5 million of the money the tax generates to pay off the settlement in installments. It would devote the rest of the money toward putting the firefighters’ pension system on a solid financial footing.

The tax would be assessed on a property’s full value, not just the portion above the homestead exemption. Approving the tax would add $25 a year for every $100,000 of a property’s appraised value.

City officials have said that if the tax does not pass, the firefighters will still be paid but over a longer timeline, using money from cuts in other departments' budgets.

City Councilwoman Stacy Head, who noted that she has been skeptical of some city spending and revenue measures in the past, said it is crucial to pass the new tax to settle a dispute that has gone on for decades and through many administrations and councils.

“We do not want to saddle our children and future generations with an obligation we have shirked for so long,” Head said.

Follow Jeff Adelson on Twitter, @jadelson.​