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EXHIBIT 5
RIORDAN & MCKINZIE
A PROFESSIONAL LAW CORPORATION
300 S. GRAND AVENUE, 29TH FLOOR
LOS ANGELES, CALIFORNIA 90071-3155
DECEMBER 29, 2000
21-088-001
Tetra Tech, Inc.
670 N. Rosemead Boulevard
Pasadena, California 91107-2190
Ladies and Gentlemen:
We have acted as counsel to Tetra Tech, Inc., a Delaware corporation (the
"Company"), in connection with the registration under the Securities Act of
1933, as amended (the "1933 Act"), of 296,667 authorized and previously issued
shares of the Common Stock (the "Shares"), $.01 par value per share, of the
Company to be sold by certain selling stockholders. This opinion is delivered to
you in accordance with the requirements of Item 601(b)(5) of Regulation S-K
under the 1933 Act in connection with the Registration Statement on Form S-3,
including all pre-effective and post-effective amendments thereto (the
"Registration Statement"), for the aforementioned sale, filed with the
Securities and Exchange Commission (the "Commission") under the 1933 Act.
In rendering the opinion set forth herein, we have made such investigations
of fact and law, and examined such documents and instruments, or copies thereof
established to our satisfaction to be true and correct copies thereof, as we
have deemed necessary under the circumstances.
Based upon the foregoing and such other examination of law and fact as we
have deemed necessary, and in reliance thereon, we are of the opinion that, the
Shares are duly authorized, validly issued, fully paid and non-assessable.
We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to this firm under the caption
"Legal Matters" in the Prospectus which is a part of the Registration Statement.
In giving such consent, we do not thereby admit that we are in the category of
persons whose consent is required under Section 7 of the 1933 Act or the rules
and regulations of the Commission thereunder.
Very truly yours,
/s/ Riordan & McKinzie
