Tetra Tech, Inc. (NASDAQ:TTEK), a leading provider of high-end consulting and engineering services in water, environment, and sustainable infrastructure, announced today that Northern Ireland Water, the region's sole provider of water and sewage services, has selected Tetra Tech to provide high-end water and wastewater sampling services for water quality protection and enhanced resiliency of their water supplies.

Tetra Tech's water and environment experts will evaluate water and wastewater conditions from locations throughout Northern Ireland, part of Northern Ireland Water's efforts to meet their regulatory water quality targets. Under the three-year contract, Tetra Tech will leverage a network of in-house water quality, health and safety, and equipment specialists to enhance the operational efficiency of the project.

"Tetra Tech has supported Northern Ireland Water to strengthen the country's water network and provide water services for decades," said Roger Argus, Tetra Tech Chief Executive Officer. "We look forward to continuing to leverage our Leading with Science^® approach to support Northern Ireland Water to deliver world-class water supplies for hundreds of thousands of homes and businesses and protect human health and the environment."

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 more than 25,000 employees working together, Tetra Tech provides clear solutions to complex problems by Leading with Science^® to address the entire water cycle, protect and restore 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.

Any statements made in this release that are not based on historical fact are forward-looking statements. Any forward-looking statements made in this release represent management's best judgment as to what may occur in the future. However, Tetra Tech's actual outcome and results are not guaranteed and are subject to certain risks, uncertainties and assumptions ("Future Factors"), and may differ materially from what is expressed. For a description of Future Factors that could cause actual results to differ materially from such forward-looking statements, see the discussion under the section "Risk Factors" included in the Company's Form 10-K and Form 10-Q filings with the Securities and Exchange Commission.

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Jim Wu, Investor Relations

Charlie MacPherson, Media & Public Relations

(626) 470-2844

Tetra Tech Awarded £18 Million Water and Wastewater Contract in Northern Ireland