After Anna Kronzer's one-story, 1940s-era Bellaire home took on a foot of water during Hurricane Harvey, news from the city permitting office came as a shock: Work done years ago by the previous homeowner would put her over a federal threshold requiring her house to be raised to current standards.

The Federal Emergency Management Agency requires that homes with substantial damage, in which repairs cost more than 50 percent of the structure's value, be brought into compliance with current building codes. That usually means elevating the house, which can cost $100,000 or more.

In Bellaire, where more than a third of the city's 6,700 homes flooded, the rule comes with a twist: Damage assessments are cumulative, which means even if Harvey exacted only 20 percent damage, a homeowner could be forced to elevate if the house also had flood repairs in 2015 and 2016.

People who can't afford it might be forced to tear down and sell, because standard flood insurance doesn't cover mitigation costs.

The rule upset homeowners like Kronzer who weren't aware of it and had never been told what their property's cumulative damage total was. It came as a surprise in a region where neither the city of Houston nor Harris County use cumulative damages. And it puts disaster-ravaged residents, eager to return home as fast as possible, at odds with a policy designed to get people out of harm's way, thrusting city officials into an awkward position.

Harris County Engineer John Blount said FEMA tried about 10 years ago to strong arm the county into using cumulative damages, but the county refused because FEMA also insists on keeping damage tallies confidential, meaning they can't be published in deed records.

"How would a buyer know he was $3,000 away from having to tear a house down before he bought it?" Blount said. "I understand it from a floodplain management standpoint, but from a practical standpoint you've got to protect buyers."

FEMA officials did not immediately respond to requests for comment.

Bellaire City Manager Paul Hofmann is convening a task force to study a broad range of flood control issues, including cumulative damages and whether to keep using them. He said no one currently employed at the city can remember when the policy – which is not mandated by city ordinance – went into effect. Blount suspects it happened when FEMA was urging other local jurisdictions to do it.

Last week, Bellaire loosened the policy so that only flood-related damages count. Previously, any improvements – even cosmetic ones, like the granite countertops and wood floors added to Kronzer's house – would add to the total. The owner of a $100,000 home that had a $25,000 renovation in the past would already be considered to have 25 percent damage before the first drop of rain fell.

City officials warned residents against making assumptions about how the policy affects them. Homeowners should work through their situation with someone at the city's permitting office before deciding what to do, Hofmann said. Not everything in a contractor's bid will necessarily count toward the damage assessment, he cautioned, and a visit to the permitting office doesn't commit the homeowner to any course of action.

FEMA allows cities to count cumulative damages – and gives them a break on their flood insurance for it – because it brings older homes into compliance with building codes faster. That's of growing importance in a world facing more frequent heavy downpours, and in a metro region where upstream development paves the way for bigger downstream floods.

It also mitigates the risk that taxpayers will be on the hook for flood damage to properties that grow rapidly in value, as they do in Bellaire. For years, National Flood Insurance Program premiums haven't kept up with losses. The program owes more than $24 billion to the U.S. Treasury.

"It is not the city of Bellaire's intent to force people out of homes," Hofmann said. "It is the city of Bellaire's intent to keep people safe."

It's largely working, according to data City Engineer James Andrews presented Oct. 2. Of the nearly 2,000 homes that flooded, only about 47, or 2 percent, were built to current standards.

Yet some residents have told Hofmann they made it unscathed through Tropical Storm Allison in 2001, through the floods of 2015 and 2016, and are willing to gamble they'll never see another Harvey.

Kronzer is now faced with the prospect of tearing down and starting over, using a combination of flood insurance, savings and contributions from relatives. She plans to elevate her new home to comply with current codes to eliminate any doubt over the future of the cumulative damage policy.

The policy is an option for cities that participate in FEMA's Community Rating System. The program scores cities on a wide range of flood control and policy measures. A community with more than 4,500 credit points is Class 1, earning 45 percent off federal flood insurance premiums for homes in the floodplain. A Class 9 city, with at least 500 points, can get a 5 percent discount.

Bellaire is a Class 7, with at least 1,500 points and a 15 percent discount, according to FEMA records.

A city can get up to 90 credit points for applying a cumulative damage standard, depending on how long the damage tally accumulates, whether it includes non-flood related improvements, and other factors. It's not clear how many points Bellaire earns for its standard or whether changing it would affect the city's overall rating and insurance discount. Hofmann said his staff was looking into it.

"From what I understand, the decision we made last week to only include flood-related damage in the cumulative costs shouldn't lower our score or our rating," he said in an email.

Kronzer said she was never informed when she bought the house in March that it already had a cumulative tally against it.

"I get where the regulation comes from," she said. "They don't want us to keep flooding. The government doesn't want to keep paying through insurance to get us whole again. But it's frustrating."

She thought buying in Bellaire was a sound financial decision. The city of about 18,600 population is encircled by southwest Houston and has a median home value of $710,000, according to the U.S. Census Bureau.

Before she closed on the house, she talked to neighbors across the street who lived there for 40 years. They informed her the street had never flooded.

Even if it had, and the house had been elevated to current standards, that wouldn't have been enough for Harvey. It still would have taken on six inches of water.