Sealing Up Holes
You can carefully look around your garage if it has a hole of any scale, and should seal it out, no matter how tiny or big it is. Snakes can find it easier to sneak through the hole of any size, since they have flexible body structure. Ideally, you should seal those holes permanently, unless you have any particular benefit of them.
Cleaning of Garage
You should be cleaning your garage regularly. Particularly, do not leave any debris unattended for a longer run. Also, do not leave used or out of use tools for a longer run. Anything that is lying in the garage in a shape of bundle or greater in quantity can be used as shelter by a snake, especially if it is taking refuge against harsh weather conditions.
Clear Area Around Garage
If your garage is located at a distance place, you should clear it off the bushes and other wild plants. They are good place for snakes to take shelter and on finding an opportunity they can enter the garage. Generally, they keep rotating the place they inhabit and finding a rather cozy place can tempt them to move there.
Mothballs can repel the snakes attack, and you should place them around the parameter of your garage. They are one of the most effective methods to keep the enemy at bay, and scare them away permanently.
Remove Pests in House
If there are any pests in the house, remove them. Also if you are keeping rats and frogs as pet, do not expose them out, because they are the most attractive food for the snakes.
Report Spotting of Snake
If you have bushes and wild plants around your garage and sometime spot a snake, you should report to the fire office, and local council, and get it removed from the area.