There are a few ways to divert water away from your chimney:
Install Flashing
Install flashing: Flashing is a thin layer of metal that is installed around the base of your chimney to help prevent water from seeping into the structure.
Install a Chimney Cap
A chimney cap is a cover that sits on top of your chimney and helps prevent water from entering the chimney flue.

Install Gutters and Downspouts
Gutters and downspouts help channel water away from the chimney and can be effective at preventing water from seeping into the structure.
Repair Any Cracks or Damage
If there are cracks or damage in the chimney, water may be able to enter the structure. Repairing these issues can help prevent water from entering the chimney.
Grade the Ground Around the Chimney
If the ground around the chimney slopes towards the structure, it can cause water to flow toward the chimney. Grading the ground so that it slopes away from the chimney can help divert water away from the structure.
Use a Chimney Waterproofing Product
There are products available that can be applied to the exterior of the chimney to help prevent water from seeping into the structure.