Victim's of August's flood shouldn't worry about their flood insurance rates increasing for the next several years, until flood hazard maps are updated, Louisiana Insurance Commissioner Jim Donelon says.

"The pricing for the National Flood Insurance Program is done in a unique way …. It's based on elevation, levees, rivers and such topographical aspects as opposed to the normal pricing structure utilized by the private flood insurance market."

Geographic characteristics change much more slowly than things that typically determine private insurance companies' rates, which are based on their experience or the claims paid out during a set number of years, Donelon said.

After the August flood, Federal Emergency Management Agency officials said on several occasions the flood hazard maps wouldn't be redrawn. The amount of rain that fell was so extraordinary there is no need to revisit the maps.

Lenders require property owners in high-risk zones to buy flood insurance. The dividing line is the 100-year flood, an event with a 1 percent chance of happening in a year. Almost all of the coverage now comes through the National Flood Insurance Program. As of Dec. 31, there were 491,275 NFIP policies in Louisiana. Of those, 460,430, or 94 percent, covered residences and 30,845, or 6 percent, covered commercial properties.

Funding limitations make it difficult to keep flood hazard maps up to date, according to FEMA. The agency focuses on areas with the greatest development and most outdated maps.

FEMA was unable to provide information Monday on the last time flood maps were redrawn for area parishes and when they might be revisited.

Even then, communities can dispute the maps or initiate changes. When FEMA unveiled new flood hazard maps in 2007, Lafayette spent years and hundreds of thousands of dollars to make alterations.

Donelon said so far his department is not fielding any complaints about increases in flood insurance premiums. U.S. Rep. Garret Graves, R-Baton Rouge, said his office isn't hearing any complaints either.

In the New Orleans metro area, where 40 percent to 50 percent of homeowners buy flood coverage, rates have actually decreased since the completion of a $15 billion levee system, Donelon said. For the rest of the state, the premiums have been flat, though some areas have seen slight increases and others decreases.

Follow Ted Griggs on Twitter, @tedgriggsbr.