The answer to 'roof water stains' is that they are typically caused by leaks in the roof or improper drainage. Symptoms may include discoloration, peeling paint, or visible water damage on the ceiling or walls below. Solutions can range from simple DIY fixes like resealing flashings or cleaning gutters, to more complex repairs like replacing damaged roof shingles or tiles.
If the water stains are widespread or you're unsure of the cause, it's best to call in a professional roofing contractor to inspect the roof and identify the source of the leak. They can then provide the appropriate repair recommendations and ensure the issue is properly addressed to prevent further damage.