Chimney leaks occur for a wide variety of reasons, but all have the same outcome: water seeps into your home. This is a serious problem, as it can cause damage to your drywall and ceiling and can also promote mold and mildew growth, which is a serious health concern and can aggravate or cause respiratory conditions. In order to prevent this from happening, you should fix a chimney leak as soon as you notice it.
If your chimney is uncovered, it will allow rainwater to fall straight down it. If your chimney does not have a chimney cover, you should install one as soon as possible to prevent further water from falling down your chimney. Chimney covers (also called chimney caps) can be found at most hardware stores and are an inexpensive way to stop water from entering your home.
Check the flashing around your chimney to ensure that it is in good working order. The flashing is the plastic or metal flat piece that goes around the base of the chimney, sealing it against the roof. If there is a crack or hole in the flashing, it will allow water to enter into your home. If this is the case, you'll need to replace the flashing. Replacement flashing can be found at most hardware stores, and is usually installed with an included adhesive. If you can afford it, choose metal flashing over plastic flashing, as it will stand up to weather exposure much better and last much longer. While you're at it, check the flashing around other roof installations, like vents and fans, to ensure that there are no other entry points for water into your home. Talk with a place like Chimney Repair from Top Hat Chimney Sweeps and Repair for more information.
Check the chimney crown, which is the large piece of masonry on the top of your chimney, for any cracks or breaks. Small breaks can be sealed using crown coating material. However, caulking can be a useful stopgap measure for large gaps since it can quickly expand and seal immediately. Larger breaks, generally big enough to fit a finger in to, require the actual masonry to be replaced to seal the leak. This should be done before the winter, as water freezing in the crack can expand it and allow runoff during a thaw to flow uninhibited into your home.