Tetra Tech, Inc. is a provider of consulting and engineering services, which is focused on water, environment, and sustainable infrastructure. The Company provides solutions to public and private clients by Leading with Science. Its segments include Government Services Group (GSG) and Commercial/International Services Group (CIG). Its GSG segment provides high-end consulting and engineering services primarily to the United States government clients (federal, state, and local). Its CIG segment provides consulting and engineering services to the United States commercial clients, and international clients inclusive of the commercial and government sectors. CIG also provides sustainable infrastructure and related environmental, engineering and project management services to commercial and local government clients across Canada, in Asia Pacific (primarily Australia and New Zealand), Europe, the United Kingdom, and Brazil.