Even if Charleston's historic buildings could be raised 10 feet to better withstand flooding, Charlestonians would balk. The structures are beautiful the way they were intended. They make for one of the country's most appealing pedestrian areas. And they hold huge cultural, historical and economic value for the area - indeed for the state.

But unless Congress acts, they also are due for a tremendous increase in flood insurance rates - up to 10 times higher, according to some real estate and insurance sources.

The reason is the Biggert-Waters Act, which requires the National Flood Insurance Program to raise rates to reflect actual flood risk.

A wide array of properties are in the crosshairs - coastal and inland, high-end and modest. But historic properties like those found in downtown Charleston or areas like the Old Village in Mount Pleasant and Rockville will be hit especially hard. They do not meet current flood standards. How could they? They were built before flood maps existed.

Winslow Hastie, chief preservation officer at the Historic Charleston Foundation (HCF), said members of Congress were taken by surprise by the extreme hardship many properties would face, and there is a bipartisan effort being made to delay for up to four years some of the most problematic parts of the bill.

Mr. Hastie enlisted the support of the National Trust for Historic Preservation and Preservation Action, which lobbies in D.C. about issues related to historic properties, and he believes the movement is taking on some momentum.

Certainly the expectation of skyrocketing coastal insurance costs has Congress' attention. As of last week, the Homeowner Flood Insurance Affordability Act had 133 co-sponsors in the House and 23 co-sponsors in the Senate.

Rep. Mark Sanford, R-S.C., and Sen. Tim Scott, R-S.C., and Sen. Lindsey Graham, R-S.C., have signed on. Even Rep. Maxine Waters, D-Calif., one of the original bill's sponsors, has done so.

As Congress reconsiders its handiwork, it should't neglect the potential consequences for historic properties.

Mr. Hastie said the steeper rates would go into full effect when a property is transferred from one owner to another. He anticipates a property owner's annual rates rising to as much as $30,000. That would certainly hurt the real estate market. And even those property owners who already own their homes could be unable to pay for their flood insurance and be forced to move or simply eliminate their coverage.

Congress is right to get its fiscal house in order, and the NFIP needs particular attention. A year ago Hurricane Sandy resulted in government payouts under the program estimated as high as $15 billion. Congress passed a law to provide a $9.7 billion increase in the NFIP's borrowing authority, from $20.7 billion to $30.4 billion, to pay flood claims related to Sandy.

The flood insurance program has encouraged coastal development where it should have been restrained by financial risk. But historic properties don't fall into that category, and shouldn't be penalized for payouts resulting from ill-advised development. Without revisions, the flood insurance bill could jeopardize the viability of some of the country's most valuable, historic assets.