Tetra Tech, Inc. provides consulting and engineering services focusing on water, environment, and sustainable infrastructure in the United States and internationally. The company operates through two segments, Government Services Group (GSG) and Commercial/International Services Group (CIG). The GSG segment offers consulting and engineering services, including water resources analysis and water management, environmental monitoring, data analytics, government consulting, waste management, and civil infrastructure master planning and resilient engineering design for facilities, as well as transportation and local development projects primarily to government clients, including federal, state, and local, as well as international development agencies.