Among the questions still swirling after Tuesday's explosive revelation that two Sewerage & Water Board pumping stations were far below their maximum capacity during Saturday’s flooding in New Orleans, one stood out: Why did the utility schedule maintenance that would take a pump off-line in one of the city’s lowest areas during August, the rainiest month of the year and the middle of hurricane season?

It’s a decision that likely didn’t cause the flooding, but it would be at odds with the policies of both Jefferson Parish and the U.S. Army Corps of Engineers, each of which operates massive pumping systems of their own in the New Orleans area.

Both those entities said they ensure that scheduled work occurs at other times of the year and, even then, they seek to limit the impact of taking a pump offline.

Those precautions do not appear to have been in place at the S&WB, which allowed two key pumping stations to fall far short of their maximum capacity Saturday because of scheduled maintenance.

Whether that comported with S&WB policy remains one of the outstanding questions in the wake of a controversy that has seen two top officials step down at the S&WB and City Hall, with more expected to be fired Thursday.

That diminished pumping capacity apparently was in place during both Saturday’s flooding and a previous, smaller flood on July 22. In both those cases, however, rainfall far exceeded the capacity of the city’s drainage system, suggesting that flooding would have occurred even if all the pumps were in operation.

One area that remained murky even after a lengthy City Council hearing on the flooding Tuesday is exactly which pumps were taken offline for routine maintenance and which were pulled over recent weeks for necessary but unexpected repairs.

Joe Becker, the embattled general superintendent of the utility, told council members Tuesday that eight of the city’s 101 major pumps were out of commission during the storm, with two down because of repairs that became necessary recently. The maintenance on others was started under contracts that were put out up to four months ago.

In addition to the eight large pumps, six of the city’s 20 smaller pumps were also out of service.

It was not clear where all those pumps were. A single pump out at the station that serves Mid-City dropped its capacity to 63 percent during the storm. Four pumps that were out of service at the 17th Street Canal station left that station at 57 percent capacity or less.

It also remained unclear how often the SW&B takes pumps offline for routine maintenance, as Becker said was the case for seven of the 14 inoperable pumps Saturday, and whether this maintenance has as little impact on the system’s overall capacity as Becker — who is likely to be relieved of his duties Thursday — claimed.

On Tuesday, Councilman Jared Brossett asked Becker, “Why would the Sewerage and Water Board wait until hurricane season to do maintenance on the pumps that were not operational?”

“We’re doing maintenance of our pumps year round. We have 121 of those pumps, and we’re doing maintenance year round,” Becker said. “Those are not just hurricane response pumps. They have to be available in November, when we have floods. They have to be available in May, when we have large rain events. We have to have those pumps available year round.”

But in Jefferson Parish, the Drainage Dpartment does not schedule any maintenance on its pumps during hurricane season, and it aims to ensure no station falls below 90 percent capacity, Drainage Director Mitchell Theriot said. Short-term repairs are regularly put off when there’s a greater than 20 percent chance of rain, Theriot said.

“Any type of project that would require a long time or taking a pump out of service, we try as best we can to wait until late September,” Theriot said. Even in cases where work must be done over the summer, the agency’s policy is to try to wrap it up in June or July, to avoid having pumps offline in August.

The Jefferson agency also tries to ensure that multiple pumps that serve the same area are not taken out of service at the same time.

With 181 pumps in 23 stations scattered across the parish, Jefferson pegs its ability to remove water from the streets at 1 inch for the first hour and a half-inch for every hour after that, the same standard used by the S&WB.

Even with all pumps operating at full capacity, that rate would be only about a quarter of the capacity necessary to quickly pump out the more than 9 inches of water that fell on Mid-City in four hours Saturday.

The offline pumps — and electrical issues that further dropped the pumping capacity for periods during the storm — may have contributed to higher floodwaters that remained on the street for longer than they would have otherwise. However, the total impact of those issues is unclear.

Theriot said he did not know whether the issues at the pump station that feeds the 17th Street Canal, which also handles water from Jefferson, caused any issues in his parish.

There was significant flooding in Old Metairie, an area that would be impacted by issues at the 17th Street station, but that area would have been unable to handle the 5.5 inches of rain it received without any flooding even under ideal circumstances, Theriot said.

“Many things come into play where it’s very difficult to give you a hard and fast answer to: How much did it affect?" Theriot said. “There’s lots of other variables to consider.”

He said he had not been made aware of any capacity issues at the station. S&WB officials were criticized Tuesday for failing to tell others in city government, including the mayor’s office and the Office of Homeland Security and Emergency Preparedness, that pumps were offline.

The U.S. Army Corps of Engineers also does not schedule planned maintenance during hurricane season for its pumps on the city’s outfall canals, though those are designed to deal with a different scenario from the one facing the S&WB on Saturday.

Those pumps — currently an interim set that will soon be replaced by permanent stations at the lake end of the canals — are needed only during hurricanes, tropical storms and other high-water events in Lake Pontchartrain, when gates on the canals must be closed and water pumped over them to drain the city.

Corps Emergency Manager Heath Jones stressed that the rarely needed canal pumps face different demands from the ones that are operated year-round by the S&WB, though the policy is always to keep the system as close as possible to 100 percent capacity.

Some of those pumps are serviced during hurricane season, if biweekly tests show any problems with them. However, if a pump can be used at all, it would be put into service during a hurricane, Jones said.

“The consequences of not doing it are too great,” he said. “If you have great consequences for life, safety and property, or you’re talking about burning up one pump, you burn up the pump.”

Meanwhile, four days after the deluge, there was still no clear picture of how much damage it caused. Damage assessors have had to knock on doors in neighborhoods that absorbed the most rain, a slow process.

Between 1 and 10 inches of water fell across New Orleans in various locations Saturday, and it took the SW&B 14 hours to fully dry out the city.

At least some questions should be answered by the outside firm Mayor Mitch Landrieu said he will hire to dig deeper into the SW&B’s operations and system capacity before and during the flood. The mayor is expected to give more details about that process this week.

The S&WB's governing board will meet Thursday to dig into some of the questions raised by the storm and consider the fates of Becker and Communications Director Lisa Martin. Landrieu, who serves as president of the S&WB, on Tuesday called for both of them to be fired.

Follow Jeff Adelson on Twitter, @jadelson.​