We have had many people ask us about “snake-proofing” their homes and yards. The honest answer is that there really is no sure-fire way to do this. However, there are things that you can do to help cut down on the chances that you might have an unpleasant encounter with a snake.
Think like a snake: Snakes like to find tight little places to hide. They are really quite timid creatures, and don't like to be “exposed“ and vulnerable to predators. They will seek out and find all kinds of small places to hide around a house and yard.
Under the house - make sure that your under-house vents have intact screens on them. This prevents not only snakes from getting under there, but it keeps out Skunks and Opossums too.
Near the house - don't stack things like pieces of wood, or empty boxes against the wall of your house. Behind and under these things are ideal hide places for snakes.
In the yard - Keep the yard tidy and don't leave empty flowerpots, or other things around. You'll make a snake's day if you do because those are ideal to hide in.
Dense ivy and brush are also ideal for snakes. Keep this pruned and somewhat sparse (so you can easily see through it), and snakes won't like it as much.
Cracks and crevices in rock walls should be filled with mortar. This will also keep spiders such as black widows from making a home there.
You can also buy snake-repellent on the internet. We have no experience with this, but the theory is that you can make a perimeter around your yard which snakes will tend to avoid. This seems like a good idea, but we're a bit skeptical, not having had any feedback from people on this, and no personal experience with these products.