Water stains were noted at a wood ceiling, immediately adjacent a skylight, at a recent home inspection in Roche Harbor on San Juan Island.  Probed with a moisture meter, the underlying ceiling cavity was dry at the time of inspection, but there obviously was water intrusion at some point in time.  The skylight flashing detail appeared to be in excellent condition, suggesting the water intrusion could have been from wind-driven rain, or that it predated the skylight installation when the roof was replaced a decade ago.  In any event, I recommended the client monitor for recurrence into the future and repair if noted.  It’s important to monitor all roof penetrations (e.g., skylights, stove flues, vent pipes, solar tubes, etc.) for water intrusion and repair immediately when/if noted.