"Tracing the origin of a leak can be challenging especially when there is no water dripping down. You could try waiting for rain or have someone use a garden hose to splash water on the roof. Once you find the suspicious spot, it's time to patch things up with a sealant or new shingles. Patching up roof leaks can be difficult for the inexperienced, and you might end up working on the wrong spot of the roof or doing a shoddy repair job. Leaks are also found in other places like flashing and the edges of roof fixtures, so repairing them isn't as simple as covering them with new shingles. To help ensure that the job is properly done, you can always count on reliable Clearwater roofing contractors like Arry's Roofing Services, Inc."
http://www.arrysroofing.com/info-articles/tracing-and-fixing-leaks-with-trusted-clearwater-fl-roofing-services/