Inspect your house carefully, looking for all possible entryways from which snakes could possibly enter. Make note of all openings, small and big.
Cover all the openings that you discover. To fill small holes, you can use an adhesive compound. Use cloth or plastic to cover the larger holes and openings. Make sure every filling is tight enough to hold against a snake pushing its head inside.
Cover sewer vents on your roof by firmly squeezing cloth into them.
Trim any tree limbs that give snakes access to your roof.
Get rid of any and all home items that may attract snakes. Get rid of mice and rats; snakes love them. Get a cat or buy a mousetrap. Properly seal your pet's food. Store meat and dairy products in the refrigerator.
Clean your house daily and throw away any meat wrappings, diapers and sanitary products. Seal these items in a plastic trash bag.