EXHIBIT 99.1 Exhibit 99.1 NEWS RELEASE May 7, 2025 Tetra Tech Reports Strong Second Quarter Results and Raises FY25 Guidance ● Record Second Quarter Revenue $1.322 billion ● Record Second Quarter Net Revenue $1.104 billion ● Record Second Quarter Adjusted Operating Income $130 million ● Increasing Quarterly Dividend +12% Y/Y ● Raising FY25 EPS Guidance Pasadena, California . Tetra Tech, Inc. (NASDAQ: TTEK), a leading provider of high-end consulting and engineering services in water, environment and sustainable infrastructure, today announced results for the second quarter ended March 30, 2025. Q2 FY25 YTD FY25 $ million (except EPS data) Reported Adjusted 1 Reported Adjusted 1 Revenue $ 1,322.1 $ 1,322.1 $ 2,742.7 $ 2,742.7 Net Revenue $ 1,103.7 $ 1,103.7 $ 2,301.0 $ 2,301.0 Operating Income $ 39.6 $ 130.1 $ 62.1 $ 267.2 EPS $ 0.02 $ 0.33 $ 0.02 $ 0.68 Year to Date Highlights ● Revenue increased 11% Y/Y to $2.74 billion ● Net Revenue increased 11% Y/Y to $2.30 billion ● Adjusted Operating Income increased 17% Y/Y to $267 million ● Adjusted EPS increased 21% Y/Y to $0.68 Second Quarter Highlights ● Revenue increased 6% Y/Y to $1.322 billion ● Net Revenue increased 5% Y/Y to $1.104 billion ● Adjusted Operating Income increased 11% Y/Y to $130 million ● Adjusted EPS increased 18% Y/Y to $0.33 ● Book-to-Bill: 1.1x (excluding USAID and Dept. of State) ● Backlog $4.09 billion, up $127 million Y/Y (excluding USAID and Dept. of State) 1 Non-GAAP financial measures which the Company believes provide valuable perspectives on its business results. Adjusted operating income and EPS exclude non-cash goodwill impairment related to USAID. Refer to tables at the end of the release and Regulation G Information for reconciliations to the comparable GAAP metrics. Recent Key Wins ● $416 million five-year multiple award contracts to deliver environmental engineering services for USACE Honolulu District ● $249 million five-year multiple award contract for planning and engineering services for USACE Mobile District ● $240 million five-year multiple award contract for planning and engineering services for USACE Middle East District ● £42 million five-year multiple award contract for stormwater management services for a U.K. water utility ● $48 million five-year multiple award contract for environmental engineering services for USACE Huntsville District ● $46 million three-year multiple award contract for planning and engineering services for USACE Los Angeles District ● £36 million three-year multiple award contract for water infrastructure services for Severn Trent Water in the U.K. Capital Allocation, Quarterly Dividend and Share Repurchase Program On May 5, 2025, Tetra Tech’s Board of Directors approved the Company’s 44 th consecutive quarterly dividend at an amount of $0.065 per share, a 12% increase year-over-year, payable on June 5, 2025, to stockholders of record as of May 23, 2025. In the second quarter, Tetra Tech repurchased $150 million of common stock. Furthermore, the Board approved an additional $500 million share repurchase program. Together with the $173 million remaining under the previously approved program at the end of the second quarter of fiscal 2025, the Company had $673 million available for share repurchase. Subsequent to the end of the second quarter, on May 5, 2025, Tetra Tech entered into an Amended and Restated Credit Agreement with a total borrowing capacity of $1.5 billion that will mature in May 2030. Chairman and CEO Comments Dan Batrack, Chairman and CEO, commented, “We generated record second quarter results for revenue and net income despite the decrease in revenue associated with the reorganization of USAID. Our growth in State and Local, U.S. Commercial, and International revenues more than offset this headwind, which resulted in net revenue and EPS exceeding consensus and the upper end of our guidance range for the quarter. We are seeing significant demand for our differentiated Leading with Science ® services in our water and environmental markets, including our high-end digital automation services for our municipal and commercial clients. “In the last month, we announced strategic acquisitions expanding our global digital technology and program management businesses. Based on our strong performance, we increased our dividend by 12% and expanded our stock buyback program by an additional $500 million. With record year-to-date performance and a strong outlook, we are raising our FY25 guidance for net revenue and EPS.” Business Outlook The following statements are based on current expectations. These statements are forward-looking, and the actual results could differ materially. These statements do not include the potential impact of transactions that may be completed or developments that become evident after the date of this release. The Business Outlook section should be read in conjunction with the information on forward-looking statements at the end of this release. During the quarter, we were notified that virtually all our contracts with USAID were terminated for convenience. Consequently, we performed an interim impairment review of the goodwill in our Global Development Services division. As a result, we reduced backlog by the value of the terminated contracts and recorded a non-cash goodwill impairment charge of $92.4 million in the second quarter of fiscal 2025. Tetra Tech has updated its guidance for fiscal year 2025 based on its current outlook, which includes the expected impact of the ongoing U.S. federal government review process. For fiscal 2025, Tetra Tech is increasing full year guidance for net revenue 2 to range from $4.400 billion to $4.765 billion and is increasing adjusted EPS 3 guidance to range from $1.42 to $1.52. For the third quarter in fiscal 2025, Tetra Tech expects net revenue to range from $1.10 billion to $1.20 billion and EPS to range from $0.35 to $0.40. Webcast Investors will have the opportunity to access a live audio-visual webcast and supplemental financial information concerning the second quarter of fiscal 2025 results through a link posted on the Company’s website at tetratech.com on May 8, 2025, at 8:00 a.m. (PT). 2 Reconciliation of the net revenue guidance to the most directly comparable GAAP measure is not available without unreasonable efforts because the Company cannot predict the magnitude and timing of all the components, including subcontractor costs, required to provide such reconciliation with sufficient precision. 3 The adjustments in our guidance for EPS are to exclude the legal contingency of $0.35 and goodwill impairment of $0.31. Reconciliation of GAAP and Non-GAAP Items In thousands (except EPS data) Three Months Ended Six Months Ended March 30, March 31, March 30, March 31, 2025 2024 2025 2024 Revenue $ 1,322,113 $ 1,251,616 $ 2,742,674 $ 2,479,883 Subcontractor costs (218,408 ) (198,989 ) (441,639 ) (412,087 ) Net revenue $ 1,103,705 $ 1,052,627 $ 2,301,035 $ 2,067,796 Operating Income $ 39,603 $ 117,683 $ 62,129 $ 228,764 Legal contingency - - 115,000 - Goodwill impairment 92,416 - 92,416 - Contingent consideration (1,931 ) 14 (2,297 ) (22 ) Adjusted Operating Income $ 130,088 $ 117,697 $ 267,248 $ 228,742 EPS $ 0.02 $ 0.28 $ 0.02 $ 0.56 Legal contingency - - 0.35 - Goodwill impairment 0.31 - 0.31 - Adjusted EPS $ 0.33 $ 0.28 $ 0.68 $ 0.56 About Tetra Tech Tetra Tech is the leader in water, environment and sustainable infrastructure, providing high-end consulting and engineering services for projects worldwide. With 30,000 employees working together, Tetra Tech provides clear solutions to complex problems by Leading with Science ® to address the entire water cycle, protect and res tore the environment, and design sustainable and resilient infrastructure. For more information about Tetra Tech, please visit tetratech.com or follow us on LinkedIn and Facebook . CONTACTS: Jim Wu, Investor Relations Charlie MacPherson, Media & Public Relations (626) 470-2844 Forward-Looking Statements This release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. The use of words such as "anticipate," "expect," "could," "may," "intend," "plan" and "believe," among others, generally identify forward-looking statements. These forward-looking statements are based on current expectations and beliefs of Tetra Tech’s management and currently available operating, financial, economic and other information, and are subject to a number of risks and uncertainties. Readers are cautioned that these forward-looking statements are only predictions and may differ materially from actual future events or results. A variety of factors, many of which are beyond our control, could cause actual future results or events to differ materially from those projected in the forward-looking statements in this release, including but not limited to: continuing worldwide political and economic uncertainties; the U.S. Administration’s potential changes to fiscal policies; the cyclicality in demand for our overall services; the fluctuation in demand for oil and gas, and mining services; risks related to international operations; concentration of revenues from U.S. government agencies and potential funding disruptions by these agencies; dependence on winning or renewing U.S. government contracts; the delay or unavailability of public funding on U.S. government contracts; the U.S. government’s right to modify, delay, curtail or terminate contracts at its convenience; compliance with government procurement laws and regulations; the impact of global pandemics; credit risks associated with certain clients in certain geographic areas or industries; acquisition strategy and integration risks; goodwill or other intangible asset impairment; the failure to comply with worldwide anti-bribery laws; the failure to comply with domestic and international export laws; the failure to properly manage projects; the loss of key personnel or the inability to attract and retain qualified personnel; the ability of our employees to obtain government granted eligibility; the use of estimates and assumptions in the preparation of financial statements; the ability to maintain adequate workforce utilization; the use of the percentage-of-completion method of accounting; the inability to accurately estimate and control contract costs; the failure to adequately recover on our claims for additional contract costs; the failure to win or renew contracts with private and public sector clients; growth strategy management; backlog cancellation and adjustments; risks relating to cyber security breaches; the failure of partners to perform on joint projects; the failure of subcontractors to satisfy their obligations; requirements to pay liquidated damages based on contract performance; the adoption of new legal requirements; changes in resource management, environmental or infrastructure industry laws, regulations or programs; changes in bank and capital markets and the access to capital; credit agreement covenants; industry competition; liability related to legal proceedings, investigations, and disputes; the availability of third-party insurance coverage; the ability to obtain adequate bonding; employee, agent, or partner misconduct; employee risks related to international travel; safety programs; conflict of interest issues; liabilities relating to reports and opinions; liabilities relating to environmental laws and regulations; force majeure events; protection of intellectual property rights; stock price volatility; the ability to impede a business combination based on Delaware law and charter documents; and other risks and uncertainties as may be described in Tetra Tech’s periodic filings with the Securities and Exchange Commission, including those described in the “Risk Factors” section of Tetra Tech’s Annual Report on Form 10-K for the fiscal year ended September 29, 2024. Readers should not place undue reliance on forward-looking statements since such information speaks only as of the date of this release. Tetra Tech does not intend to update forward-looking statements and expressly disclaims any obligation to do so. Non-GAAP Financial Measures To supplement the financial results presented in accordance with generally accepted accounting principles in the United States (“GAAP”), we present certain non-GAAP financial measures within the meaning of Regulation G under the Securities Exchange Act of 1934, as amended. We provide these non-GAAP financial measures because we believe they provide a valuable perspective on our financial results. However, non-GAAP measures have limitations as analytical tools and should not be considered in isolation and are not in accordance with, or a substitute for, GAAP measures. In addition, other companies may define non-GAAP measures differently which limits the ability of investors to compare non-GAAP measures of Tetra Tech to those used by our peer companies. A reconciliation of these non-GAAP financial measures to the most directly comparable GAAP financial measures is set forth above in this release. Tetra Tech, Inc Consolidated Balance Sheets (unaudited - in thousands, except par value) March 30, September 29, 2025 2024 Assets Current assets: Cash and cash equivalents $ 179,433 $ 232,689 Accounts receivable, net 1,223,214 1,051,461 Contract assets 134,106 129,678 Prepaid expenses and other current assets 129,425 113,555 Total current assets 1,666,178 1,527,383 Property and equipment, net 66,048 73,065 Right-of-use assets, operating leases 185,499 177,950 Goodwill 1,913,134 2,046,569 Intangible assets, net 136,784 160,585 Deferred tax assets 106,137 105,529 Other non-current assets 110,524 101,595 Total assets $ 4,184,304 $ 4,192,676 Liabilities and Equity Current liabilities: Accounts payable $ 262,300 $ 197,440 Accrued compensation 242,017 332,096 Contract liabilities 373,591 351,738 Short-term lease liabilities, operating leases 65,870 63,419 Current portion of long-term debt 250,000 - Current contingent earn-out liabilities 20,497 26,934 Other current liabilities 302,240 247,900 Total current liabilities 1,516,515 1,219,527 Deferred tax liabilities 27,193 30,162 Long-term debt 764,189 812,634 Long-term lease liabilities, operating leases 143,242 140,095 Non-current contingent earn-out liabilities 10,773 21,812 Other non-current liabilities 148,611 138,033 Total liabilities 2,610,523 2,362,263 Equity: Preferred stock - authorized, 2,000 shares of $0.01 par value; no shares issued and outstanding at March 30, 2025 and September 29, 2024 - - Common stock - authorized, 750,000 shares of $0.01 par value; issued and outstanding, 263,503 and 267,717 shares at March 30, 2025 and September 29, 2024, respectively 2,635 2,677 Additional paid-in capital - 35,900 Accumulated other comprehensive loss (153,180 ) (78,875 ) Retained earnings 1,724,203 1,870,620 Tetra Tech stockholders' equity 1,573,658 1,830,322 Noncontrolling interests 123 91 Total stockholders' equity 1,573,781 1,830,413 Total liabilities and stockholders' equity $ 4,184,304 $ 4,192,676 Tetra Tech, Inc Consolidated Statements of Income (unaudited - in thousands, except per share data) Three Months Ended Six Months Ended March 30, March 31, March 30, March 31, 2025 2024 2025 2024 Revenue $ 1,322,113 $ 1,251,616 $ 2,742,674 $ 2,479,883 Subcontractor costs (218,408 ) (198,989 ) (441,639 ) (412,087 ) Other costs of revenue (889,523 ) (845,132 ) (1,865,376 ) (1,669,803 ) Gross profit 214,182 207,495 435,659 397,993 Selling, general and administrative expenses (84,094 ) (89,798 ) (168,411 ) (169,251 ) Legal contingency costs - - (115,000 ) - Contingent consideration - fair value adjustments 1,931 (14 ) 2,297 22 Impairment of goodwill (92,416 ) - (92,416 ) - Income from operations 39,603 117,683 62,129 228,764 Interest expense, net (8,491 ) (9,883 ) (15,709 ) (19,461 ) Income before income tax expense 31,112 107,800 46,420 209,303 Income tax expense (25,700 ) (31,341 ) (40,230 ) (57,864 ) Net Income 5,412 76,459 6,190 151,439 Net income attributable to noncontrolling interests (24 ) (13 ) (55 ) (21 ) Net income attributable to Tetra Tech $ 5,388 $ 76,446 $ 6,135 $ 151,418 Earnings per share attributable to Tetra Tech: Basic $ 0.02 $ 0.29 $ 0.02 $ 0.57 Diluted $ 0.02 $ 0.28 $ 0.02 $ 0.56 Weighted-average common shares outstanding: Basic 265,728 267,420 266,819 267,095 Diluted 267,439 269,375 269,691 269,125 Tetra Tech, Inc. Consolidated Statements of Cash Flows (unaudited - in thousands) Six Months Ended March 30, March 31, 2025 2024 Cash flows from operating activities: Net income $ 6,190 $ 151,439 Adjustments to reconcile net income to net cash provided by operating activities: Depreciation and amortization 29,939 37,215 Amortization of stock-based awards 17,027 15,617 Deferred income taxes (6,164 ) (8,049 ) Provision for losses on accounts receivables 3,331 - Impairment of goodwill 92,416 - Fair value adjustments to contingent consideration (2,297 ) - Gain on cash surrender value of life insurance policies (1,599 ) - Other non-cash items 4,267 1,032 Changes in operating assets and liabilities, net of effects of business acquisitions: Accounts receivable and contract assets (203,055 ) (23,195 ) Prepaid expenses and other assets (28,322 ) (33,412 ) Accounts payable 66,917 36,406 Accrued compensation (83,088 ) (74,291 ) Contract liabilities 37,354 34,801 Income taxes receivable/payable (3,253 ) (18,556 ) Cash settled contingent earn-out liability (7,420 ) - Other liabilities 84,997 (6,826 ) Net cash provided by operating activities 7,240 112,181 Cash flows from investing activities: Payments for business acquisitions, net of cash acquired (5,680 ) (71,796 ) Capital expenditures (9,372 ) (7,463 ) Proceeds from sale of assets 350 98 Proceeds from company-owned life insurance policies 1,934 - Net cash used in investing activities (12,768 ) (79,161 ) Cash flows from financing activities: Proceeds from borrowings 215,000 180,000 Repayments on long-term debt (15,000 ) (110,000 ) Repurchases of common stock (174,984 ) - Shares repurchased for tax withholdings on share-based awards (13,848 ) (12,781 ) Payments of contingent earn-out liabilities (14,445 ) (22,112 ) Stock options exercised 171 1,462 Dividends paid (30,900 ) (27,781 ) Principal payments on finance leases (3,431 ) (3,155 ) Net cash provided by (used in) financing activities (37,437 ) 5,633 Effect of exchange rate changes on cash and cash equivalents (10,291 ) 2,810 Net increase (decrease) in cash and cash equivalents (53,256 ) 41,463 Cash and cash equivalents at beginning of period 232,689 168,831 Cash and cash equivalents at end of period $ 179,433 $ 210,294 Supplemental information: Cash paid during the period for: Interest $ 16,180 $ 20,093 Income taxes, net of refunds received of $4.6 million and $2.4 million $ 47,987 $ 84,916 Noncash financing activities: Excise taxes accrued but not paid $ 1,267 - Tetra Tech, Inc. Regulation G Information March 30, 2025 Reconciliation of Revenue to Revenue, Net of Subcontractor Costs ("Net Revenue") (in millions) 2024 2025 2022 2023 1st Qtr 2nd Qtr 6 Mos 3rd Qtr 9 Mos 4th Qtr Total 1st Qtr 2nd Qtr 6 Mos Consolidated Revenue 3,504.0 4,522.6 1,228.3 1,251.6 2,479.9 1,344.3 3,824.2 1,374.5 5,198.7 1,420.6 1,322.1 2,742.7 Subcontractor Costs (668.5 ) (771.5 ) (213.1 ) (199.0 ) (412.1 ) (234.7 ) (646.8 ) (230.0 ) (876.8 ) (223.3 ) (218.4 ) (441.7 ) Net Revenue 2,835.5 3,751.1 1,015.2 1,052.6 2,067.8 1,109.6 3,177.4 1,144.5 4,321.9 1,197.3 1,103.7 2,301.0 GSG Segment Revenue 1,820.9 2,158.9 575.0 597.1 1,172.2 640.6 1,812.7 670.6 2,483.4 751.8 661.4 1,413.2 Subcontractor Costs (484.4 ) (523.4 ) (132.3 ) (130.6 ) (263.0 ) (152.3 ) (415.3 ) (158.1 ) (573.4 ) (150.6 ) (140.5 ) (291.1 ) Net Revenue 1,336.5 1,635.5 442.7 466.5 909.2 488.3 1,397.4 512.5 1,910.0 601.2 520.9 1,122.1 CIG Segment Revenue 1,738.4 2,424.6 669.1 671.2 1,340.3 723.6 2,063.9 722.9 2,786.7 688.2 678.9 1,367.1 Subcontractor Costs (239.3 ) (309.0 ) (96.6 ) (85.1 ) (181.7 ) (102.2 ) (283.9 ) (90.9 ) (374.8 ) (92.1 ) (96.1 ) (188.2 ) Net Revenue 1,499.1 2,115.6 572.5 586.1 1,158.6 621.4 1,780.0 632.0 2,411.9 596.1 582.8 1,178.9 Reconciliation of Net Income Attributable to Tetra Tech to Adjusted EBITDA (in thousands) 2024 2025 2022 2023 1st Qtr 2nd Qtr 6 Mos 3rd Qtr 9 Mos 4th Qtr Total 1st Qtr 2nd Qtr 6 Mos Net Income Attributable to Tetra Tech 263,125 273,420 74,972 76,446 151,418 85,810 237,228 96,154 333,382 747 5,388 6,135 Income Tax Expense 85,602 127,526 26,523 31,341 57,864 32,894 90,757 39,266 130,023 14,530 25,700 40,230 Interest Expense 1 11,584 46,537 9,578 9,883 19,461 9,912 29,374 7,897 37,271 7,218 8,491 15,709 Depreciation 13,859 19,980 6,951 5,637 12,588 5,713 18,301 5,421 23,722 5,402 5,248 10,650 Amortization 13,174 41,226 12,533 12,094 24,627 13,790 38,417 11,538 49,955 10,660 8,629 19,289 FX Hedge Gain (19,904 ) (89,402 ) - - - - - - - - - - EBITDA 367,440 419,287 130,557 135,401 265,958 148,119 414,077 160,276 574,353 38,557 53,456 92,013 Contingent Consideration - 12,255 (37 ) 14 (22 ) 500 477 2,064 2,541 (366 ) (1,931 ) (2,297 ) Goodwill Impairment - - - - - - - - - - 92,416 92,416 Acquisition & Integration Expenses 2 - 49,554 - - - - - 7,138 7,138 - - - Legal Contingency - - - - - - - - - 115,000 - 115,000 COVID-19 Credits (6,486 ) - - - - - - - - - - - Adjusted EBITDA 360,954 481,096 130,520 135,415 265,936 148,619 414,554 169,478 584,032 153,191 143,941 297,132 1 Includes write-off of deferred debt origination fees of $3.8M in fiscal 2023 2 Includes lease impairment charge of $16.4M in fiscal 2023

the item shown at left

other guidance in this release

Text is the filed exhibit, verbatim.