That musty smell downstairs usually points to water, and basements show moisture problems earlier than any other part of the house. This section covers sump pumps, waterproofing and seepage, foundations and floors, and humidity and musty odors that linger after the puddles are gone. Flood cleanup guides round it out for the days after heavy rain or a burst pipe. Begin with the source of the water if you can find it, and use the guides to plan the next step.