WASHINGTON >> Houston’s population is growing quickly, but when Harvey hit last weekend there were far fewer homes and other properties in the area with flood insurance than just five years ago, according to an Associated Press investigation.

The sharp, 9 percent drop in coverage means many residents fleeing Harvey’s floodwaters have no financial backup to fix up their homes and will have to draw on savings or go into debt — or perhaps be forced to sell.

A former head of the federal flood insurance program called the drops “unbelievable” and criticized the Federal Emergency Management Agency, which oversees the program.

“When you start to see policies drop like this, FEMA should have done something about this,” said Robert Hunter, who ran the program in the late ’70s. He estimates that fewer than two of 10 homeowners with flood damage have flood insurance.

Houston’s Harris County has 25,000 fewer flood-insured properties than it did in 2012, according to the AP’s review of FEMA data.

In percentage terms, the drop was even more dramatic in certain sections of the county: In Pasadena, just southeast of Houston, policies were down nearly 20 percent. Baytown, east of Houston, saw a 22 percent drop. The trouble extended beyond Houston, too. Jefferson County, home to cities like Beaumont and Port Arthur, which Harvey hit today, saw a bigger drop. That county fell from 25,818 policies to 19,773 in the past five years, a 23 percent decrease.

The current head of the flood insurance program, Roy Wright, attributed much of the drop in the Houston area to Congress’ decision in 2012 to raise premiums, and said there is a “true insurance gap” across the country: Only half of the 10 million properties in the U.S. that he said need flood coverage have bought it.

He said he is working to close to gap, but noted that the decision to keep or drop coverage largely lies with individuals.

“I can educate and make the product available, but ultimately this is a pocketbook decision made by each individual homeowner,” said Wright, director of the National Flood Insurance Program.

Experts say another reason for the lack of coverage in the Houston area was that the last big storm, Tropical Storm Allison, was 16 years ago. Fear of another flood faded.

Jesse Trubia, president of a metal fabrication company, decided to pass on flood insurance when he moved to his two-story home on the outskirts of Houston several years ago. That decision will now cost him up to $30,000, he estimated. Up to one foot of water seeped into his home in Cypress.

In total, Harris County residents were paying premiums on nearly 250,000 flood insurance policies in June, down from almost 275,000 policies at the end of 2012. There were roughly 1.75 million housing units in Harris County, but that includes apartment and condominium buildings, making it an imperfect figure to try to calculate what overall percentage of families are covered by flood insurance.

The number of policies in Houston itself fell from 133,000 to 119,000, an 11 percent drop — roughly in line with the trend nationally. Over the same period, the number of flood policies across the U.S. dropped 10 percent, to 4.9 million.

Jiles Daniels, a retired oil company manager, never wavered when he bought flood insurance on both his homes: one in Houston and another on an island near Cleveland, northeast of Houston. The cost is considerable: about $1,800 a year in premiums for the two houses combined. He thinks it’s worth it: The lower level of his island house went about 4 feet under water, he estimates, though his city home had been spared so far.

Under current rules, most homeowners with mortgages living in high risk areas for flooding, called Special Flood Hazard Zones, must buy flood insurance.

Most of the Houston area falls outside those most vulnerable zones, and many homeowners who aren’t forced to have coverage have decided to do without.

One problem with the flood risk maps highlighted by Tropical Storm Harvey: They don’t take into account the risk of flooding from overcapacity drainage sewers and ditches or from water flowing toward a sewer or bayou. More than half of the flooding in Harris County over the years has been due to such problems.

For Ronnie Walsh, 45, flood insurance was out of the question. He was laid off from a factory job in June and even before that money was tight.

On Monday, Walsh was evacuated from his east Houston home by rescuers in helicopters after water started seeping into the house. He and his two sons, ages 4 and 6, had just a few bags of belongings with them when they arrived at a downtown convention center. They spent the night on flattened boxes, wondering how much damage their house sustained.

He fears everything is gone.