In East Baton Rouge, half the homes inundated in the recent storms aren't in areas where flood insurance is required by lenders, preliminary parish numbers show.

Of an estimated 54,611 residential structures damaged in the storms, 27,494 were not in what the federal government deems a "high-risk area," according to city-parish assessments. 

Mayor-President Kip Holden said Thursday about half the people who took on water lived in areas where residents aren't required by lenders to buy flood insurance. Many places experienced flooding that never had before, from the Sherwood Forest corridor to much of north Baton Rouge, Holden said.

The Federal Emergency Management Agency recommends that every homeowner buy flood insurance, but in practice most people decide based on whether or not they live in a high-risk flood zone, as determined by FEMA.

The head of the Louisiana Bankers Association calls FEMA's flood maps "the holy grail of lending." But in a written statement Thursday, CEO Robert Taylor said the vital documents are flawed.

"If the property is not in the flood hazard area then usually the borrower does not purchase flood insurance as it is not required. The flaw in this process is the reliability of the flood maps," Taylor wrote.

"I ask you, do you have confidence in the flood maps that determine if your property is safe from flooding?"

FEMA officials did not respond to a request to respond to Taylor's statement.

High-risk areas, also known as "special flood hazard zones," are ones that meteorologists predict have a one percent chance of flooding every year. Put another way, forecasters would expect those places to flood on average once every hundred years.

Moderate- to low-risk areas, or non-special flood hazard areas, are locations expected to flood once every 100 to 500 years.

The storms that caused recent flooding in Louisiana have been described as an even rarer thousand-year event.

In Louisiana everyone lives in a flood zone, FEMA says. The only distinction is whether a property has a comparatively higher or lower risk of taking on water from year to year. Anyone may buy flood insurance from the government, but most people just look to see if they live in a high-risk flood zone and will be required by their lenders to have a flood policy.

"Many, many people use that as a test," said FEMA spokesman Kurt Pickering.

"'If you don't live in the (special flood hazard zone) you don't need flood insurance.' … If I've heard that once I've heard it a hundred times. And it can flood anywhere. I wish we could educate people to not think that way."

One of the uninsured flood victims was Metro Councilwoman Erika Green, whose district is smack-dab in the middle of the parish, equally far from the Amite River and the Mississippi River. Like many of her constituents, she decided not to take on the extra expense of flood insurance because she isn't in an area where it's required of people with a mortgage.

"My entire district has been pretty much put under water," she said.

People who weren't required to buy flood insurance simply aren't ready for the financial fallout, Green said. 

"When you're in a flood zone, you prepare for that," she remarked.

Central Mayor Jr. Shelton wonders whether eventually everyone will be required to hold a flood insurance policy, adding that he's not sure it would be a bad idea.

Mandatory coverage would cause rates to fall, but it's impossible to estimate by how much, said Insurance Commissioner Jim Donelon.

"Requiring it for everybody in America is impractical. That's not going to happen," Donelon said.

However, requiring every borrower who gets a mortgage from a federally regulated lender to buy flood coverage may be possible, Donelon said. Another way of lowering the costs for individuals would be to create a combined federal flood and earthquake insurance program — earthquake coverage is a state program, not a federal one, he noted.

Making lenders require earthquake coverage on mortgages in high-risk zones in the same way that flood insurance is done would dramatically increase the number of policies and spread the risk, making the coverage more affordable, Donelon said. Congress will look at reauthorizing the National Flood Insurance Program in 2017, and those ideas are worthy of debate, he said.

Senator Bill Cassidy said people who live 10, even 20 feet above sea level may need to look at acquiring flood insurance, but it's not for the government to make that decision.

"People take their own risks, and this is a free society," Cassidy said, adding that the downside of deciding not to carry insurance could be insufficient money to rebuild after a catastrophe.

Metro Councilwoman Donna Collins-Lewis — whose district is home to many uninsured flood victims who didn't live in high-risk areas — said they should be compensated by the federal government for their losses differently than people who live in high-risk flood zones.

People make housing and insurance decisions based on FEMA's information, she said.

"Something needs to happen at the federal level," she said.

William Daniel, the city-parish's chief administrative officer, said people in low-risk zones may not want the federal to acknowledge their homes should have been in a high-risk area if that means they will have to start buying flood insurance.

Congressman Garret Graves said the federal response to the flood should have special provisions, but at a regional, rather than personal level. If the U.S. government gives a relief package similar to the one the northeast received following Hurricane Sandy, projects like the Comite River Diversion Canal could finally be complete. The canal, which remains unfinished decades after the project was launched, is designed to reduce flooding along the Comite and Amite rivers. 

When asked if the federal flood maps could have lulled people in lower-risk areas into a false sense of security, Graves pointed out that the recent storms were "a complete anomaly," and that flood maps are geared more at looking at 100 to 500-year events.

Graves and Cassidy both focused on the failure of government to build flood-control structures like the diversion canal.

"There is some government culpability here," Graves said.

Follow Steve Hardy on Twitter, @SteveRHardy.