If you're termite free now, clear untreated wood from around the house, you can get DIY treatment at Home Depot/Lowes. Spray around the base of the house, on the ground for 4-6 feet from the wall and the lower edge of where the concrete meets the siding on the house. If there's no wood around the house to get started on, you'll likely only have to retreat every 5 years or so to stay termite free.