When moisture ants move indoors, they often nest in wood that is moisture damaged. They frequently find damaged wood in areas like bath traps. They sometimes nest inside walls where there is a plumbing leak. There have been cases of these ants nesting in damp soil in crawlspaces. In these situations, the workers made mounds of excavated soil in the crawl space.
If the ants have nested in damp or damaged wood, correcting the moisture problem and replacing the wood will be a priority. In damp or humid areas, treated wood may be a good replacement.