Three-quarters of the earth is covered by water -- and as recent catastrophes suggest, your valuables can go under, too. In downtown Chicago last year, vital archives were ruined when a tunnel under the Chicago River sprang a leak. After the World Trade Center bombing, last February, hose-doused documents were further damaged by improper handling. And when Des Moines was awash this past summer, a number of businesses lost irreplaceable information.

If your sprinkler system lets loose on files or photos, don't despair. Disaster-recovery specialists at the Winthrop Group, an organization of business and technology historians in Cambridge, Mass., have issued precautions for treating water-soaked paper valuables. Here are a few:

Reduce temperature. In summer, turn on air-conditioning; in winter, turn off heat.
Create air flow; avoid stagnant moist air by opening doors and windows and using fans and dehumidifiers.
Don't open or close wet books or separate single sheets.
Move valuable materials to a freezer facility as quickly as possible. Freeze-drying is usually the most effective method for removing water, but it's expensive: expect to be charged $45 to $60 per cubic foot of documents.
For further guidance, call the Winthrop Group at 617-497-0777. Other specialists: Munters Moisture Control, 800-422-6379; BMS Catastrophe, 800-433-2940; Document Reprocessors, 800-437-9464; Disaster Recovery Services, 800-856-3333; and MBK Consulting, 614-447-8032.