Basis of Presentation	3 Months Ended
Dec. 27, 2015
Basis of Presentation
Basis of Presentation	1. Basis of Presentation The accompanying unaudited condensed consolidated financial statements and related notes of Tetra Tech, Inc. (“we,” “us” or “our”) have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. They do not include all of the information and footnotes required by GAAP for complete financial statements and, therefore, should be read in conjunction with the audited consolidated financial statements and related notes contained in our Annual Report on Form 10-K for the fiscal year ended September 27, 2015. These financial statements reflect all normal recurring adjustments that are considered necessary for a fair statement of our financial position, results of operations and cash flows for the interim periods presented. The results of operations and cash flows for any interim period are not necessarily indicative of results for the full year or for future years. We report our water resources, water and wastewater treatment, environment and infrastructure engineering activities in our Water, Environment and Infrastructure (“WEI”) reportable segment. Our Resource Management and Energy (“RME”) reportable segment includes our natural resources, energy, waste management, remediation, utilities and international development services. We report the results of the wind-down of our non-core construction activities in the Remediation and Construction Management (“RCM”) reportable segment. In the first quarter of fiscal 2016, we re-aligned certain operating units within our reportable segments to improve organizational effectiveness by better aligning operations with similar clients and projects (see Note 10, “Reportable Segments” for further discussion). Prior year amounts for reportable segments have been revised to conform to the current-year presentation.

1. Basis of Presentation

The accompanying unaudited condensed consolidated financial statements and related notes of Tetra Tech, Inc. (“we,” “us” or “our”) have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. They do not include all of the information and footnotes required by GAAP for complete financial statements and, therefore, should be read in conjunction with the audited consolidated financial statements and related notes contained in our Annual Report on Form 10-K for the fiscal year ended September 27, 2015.

These financial statements reflect all normal recurring adjustments that are considered necessary for a fair statement of our financial position, results of operations and cash flows for the interim periods presented. The results of operations and cash flows for any interim period are not necessarily indicative of results for the full year or for future years.

We report our water resources, water and wastewater treatment, environment and infrastructure engineering activities in our Water, Environment and Infrastructure (“WEI”) reportable segment. Our Resource Management and Energy (“RME”) reportable segment includes our natural resources, energy, waste management, remediation, utilities and international development services. We report the results of the wind-down of our non-core construction activities in the Remediation and Construction Management (“RCM”) reportable segment. In the first quarter of fiscal 2016, we re-aligned certain operating units within our reportable segments to improve organizational effectiveness by better aligning operations with similar clients and projects (see Note 10, “Reportable Segments” for further discussion). Prior year amounts for reportable segments have been revised to conform to the current-year presentation.