Unless the U.S. Senate votes today to slow things down, owners of historic buildings like those in Charleston could see their flood insurance rates multiply 10 times or more.

As could owners of buildings in areas considered vulnerable to floods - here and across the country.

At issue is the Homeowner's Flood Insurance Affordability Act (HFIAA), which wisely puts off such staggering increases until FEMA completes an affordability study, and Congress and FEMA can find solutions to unaffordable premiums.

The current bipartisan bill has received broad support in the Senate, including 28 co-sponsors. Eight of them (including South Carolina's Tim Scott and Lindsey Graham) are Republicans. Sixty votes are needed to advance the measure for an up-or-down vote,

Advocates are less certain about support in the House.

The Historic Charleston Foundation, which supports the legislation, is urging its constituents to write their congressmen and urge them on.

If the Senate agrees to keep the bill open for discussion, it could vote on the bill itself as early as Thursday.

The HFIAA was introduced when it became apparent that the Biggert-Waters Act would financially devastate homeowners and business owners around the country. The act was intended to restore the solvency of the National Flood Insurance Program, which was driven to the verge of bankruptcy after Hurricane Katrina. But its unintended consequences would cause insurance premiums to skyrocket, even for many properties with no history of flooding and properties built exactly according to government standards.

In the case of historic structures, Historic Charleston Foundation's chief preservation officer Winslow Hastie said owners' rates would multiply because the houses are not elevated as is now required in flood zones. They couldn't be, of course. And they were built before flood maps had been considered.

But the Lowcountry should be alarmed by the dramatic costs that would come to a wide array of homeowners, not just those who live in historic areas but also those who live near rivers or the ocean.

The National League of Cities, National Association of Realtors, National Association of Homebuilders, American Bankers' Association and Independent Community Bankers' Association have all endorsed the HFIAA, which would likely drive some homeowners out of their houses and lower the value of houses impacted by Biggert-Waters.

In a recent story in The Post and Courier, Prentiss Findlay reported that a $420,000 sales contract fell through for a home on Oak Island when the buyer learned that the flood insurance would increase from $1,000 a year to somewhere between $12,000 and $18,000 because of Biggert-Waters.

Unless Congress addresses the problem by passing the Homeowners Flood Insurance Affordability Act, the economic effects on this area could be disastrous.