CORPORATE OFFICES

Tetra Tech, Inc.
3475 East Foothill Boulevard
Pasadena, California 91107
Telephone: (626) 351-4664
Fax: (626) 351-1188

TRANSFER AGENT AND REGISTRAR

U.S. Stock Transfer Corporation
1745 Gardena Avenue
Second Floor
Glendale, California 91204

STOCK LISTING

The Company's common stock is traded on the Nasdaq National Market (Symbol: TTEK)

SHAREHOLDER INQUIRIES

Investor Relations
Tetra Tech, Inc.
3475 East Foothill Boulevard
Pasadena, California 91107
Telephone: (626) 351-4664
Fax: (626) 351-1188
E-Mail: IR@tetratech.com
Website: www.tetratech.com

FORM 10-K

The Company's Form 10-K may be obtained by writing to Investor Relations. The Form 10-K is also available in the financial downloads section.