Tetra Tech, Inc. engages in the provision of consulting and engineering services that focus on water, environment, infrastructure, renewable energy, and international development. The company is headquartered in Pasadena, California and currently employs 30,000 full-time employees. The company provides solutions to complex problems by Leading with Science to address the entire water cycle, protect and restore the environment, design sustainable and resilient infrastructure, and support the clean energy transition. The company operates through two segments: Government Services Group (GSG) and Commercial/International Services Group (CIG). Its GSG segment provides consulting and engineering services primarily to United States (U.S.) government clients and international development agencies worldwide. CIG segment primarily provides consulting and engineering services to U.S. commercial clients and international clients that include both commercial and government sectors. Its CIG segment also provides sustainable infrastructure and related environmental, engineering and project management services to commercial and local government clients.