The I-4 corridor sits in one of the most lightning-prone regions in the country, and Deltona is squarely in it. From June into September, the sea breezes off both coasts collide over central Florida most afternoons and drop a violent hour of rain, wind, and lightning on the way through. Your chimney is the tallest, most exposed thing on the house, and it takes that pounding daily for an entire season: driving rain against the crown, wind working at the cap, water probing every joint in the flashing.
Chimney leaks almost never announce themselves at the chimney. Water follows framing and drywall, so the evidence shows up as a ceiling stain a few feet from the fireplace, paint bubbling in a corner, or a musty smell in a room that gets no use. Effective chimney leak repair starts with finding the true entry point (cracked crown, tired flashing, rusted cover, or masonry that's simply saturated), because sealing the wrong spot doesn't stop the water, it just sends it somewhere new. On Deltona's many one-story ranch homes the flashing line is close to the living space, which is why a small flashing failure here tends to show up indoors faster than homeowners expect.
Prevention is cheaper than chasing stains. A breathable water repellent (one that sheds rain but lets trapped vapor escape) applied before the storm pattern sets in gives brick a fighting chance against four months of daily soakings. Chimney waterproofing in the drier months, paired with a crown and flashing check, is one useful habit for an older masonry chimney in this part of Florida.