As you might expect we have had a number of water damage claims the last few weeks. Since all homeowners policies exclude flood coverage there are really two ways that you can insure against rain water damage. First the federal government provides for flood protection through the national flood insurance program. https://www.fema.gov/national-flood-insurance-program This is relatively expensive coverage but if you are willing to spend the money you can get good risk protection.
The other coverage is water backup coverage. This coverage can be added to most homeowners policies and it usually gives you a little coverage (2,000ish to 25,000ish) for a loss caused by water which backs up through sewers, drains, sump pumps, etc. Not great coverage but it gives you a little risk protection if you have a finished basement or appliances in the basement or really anything around your sump pump that could be ruined or damaged by water.