The question an adjuster asks is what caused the water and how fast you acted. Sudden and accidental events are the textbook covered cause. Slow, long-term leaks are usually denied as maintenance, because the policy expects you to fix a known drip.
Two big gaps surprise homeowners: surface flooding (rising creeks, storm runoff) is never covered by a standard policy and needs NFIP flood insurance, and sewer or drain backup needs an inexpensive backup endorsement to be covered.
To protect the claim, photograph and video everything before cleanup, stop the water source, and use a restoration company that provides adjuster-ready moisture readings and a documented scope. Coverage always depends on your specific policy language.