To avoid a household of unwanted guests who come looking for food and water, make a nontoxic, homemade repellent.
Pour equal amounts of water and white vinegar into a spray bottle, and shake to mix. Then spritz the solution in water-resistant areas where ants are common, such as kitchen floors or the crevices in painted baseboards from which the pests often enter. You can also use the repellent outside, spraying patios, porches, and picnic tables before family and friends gather.
source:http://www.marthastewart.com/photogallery/summer-homekeeping-solutions#s...