2008-05-17 00:45:52 -

- Insituform Technologies, Inc. David A. Martin, 636-530-8000 Vice President and Chief Financial Officer or Joele Frank, Wilkinson Brimmer Katcher Matthew Sherman / Dan Katcher 212-355-4449 Insituform Technologies, Inc. (Nasdaq Global Select Market: INSU) today noted Water Asset Management (WAM)'s last-second SEC filing admitting that it was a short-seller of Insituform and has made misleading statements about one of its

director nominees throughout the proxy contest. WAM's disclosure, in which it finally corrects the misleading information it has provided to stockholders throughout the proxy contest, arrives on the last business day before the Company's May 19, 2008 Annual Meeting of Stockholders. The Company stated:

A month after WAM began mailing its definitive proxy statement to Insituform stockholders, and on the very eve of the stockholder vote, WAM has finally admitted that its principals have a history of shorting Insituform's stock. We believe this last-second admission by WAM conclusively demonstrates that WAM's interests are not aligned with those of other stockholders, and belies WAM's claims to be a long-term investor in Insituform.

In its revised proxy statement, WAM also acknowledges that it had falsely claimed that one of its nominees, Mr. Vande Steege, is the former Chief Executive Officer of a Fortune 500 company, when it is clear that he never held that title.

This filing demonstrates that WAM has resorted to a campaign of misstatements, distortions and misrepresentations in its attempt to take control of Insituform and its Board of Directors. This last-second disclosure was presented at the most "stockholder unfriendly" time possible, depriving stockholders of the opportunity to fully consider this critical information in making their voting decisions.

Time is short, but stockholders can still vote the WHITE proxy card to support their Board. It is important to remember that only the latest dated proxy card counts. For this reason, stockholders are urged to vote only Insituform's WHITE proxy card and to discard WAM's blue proxy card. If stockholders have previously voted a blue card, even to withhold their vote from the dissident group's nominees, they are urged to please take the time today to vote the WHITE proxy card. Stockholders with questions or who need assistance voting their shares may call the Company's proxy solicitor, Innisfree M&A Incorporated, at (888) 750-5834.

About Insituform

Insituform Technologies, Inc. is a leading worldwide provider of proprietary technologies and services for rehabilitating sewer, water and other underground piping systems without digging and disruption. More information about the Company can be found on its Internet site at www.insituform.com.

Additional Information

Insituform has filed a definitive proxy statement with the Securities and Exchange Commission ("SEC") in connection with its 2008 Annual Meeting. Insituform's stockholders are strongly advised to read the definitive proxy statement carefully, as it contains important information. Free copies of the definitive proxy statement, and any amendments or supplements thereto, and other materials filed by Insituform with the SEC will be available free of charge on the SEC's website at www.sec.gov, on Insituform's website at www.insituform.com under Investors/SEC or by directing requests to Insituform's proxy solicitor, Innisfree M&A Incorporated, toll free at (888) 750-5834.

Forward-Looking Statements

The Private Securities Litigation Reform Act of 1995 provides a "safe harbor" for forward-looking statements. The Company makes forward-looking statements in this document that represent the Company's beliefs or expectations about future events or financial performance. These forward-looking statements are based on information currently available to the Company and on management's beliefs, assumptions, estimates and projections and are not guarantees of future events or results. When used in this document, the words "anticipate," "estimate," "believe," "plan," "intend," "may," "will" and similar expressions are intended to identify forward-looking statements, but are not the exclusive means of identifying such statements. Such statements are subject to known and unknown risks, uncertainties and assumptions, including those referred to in the "Risk Factors" section of the Company's Annual Report on Form 10-K for the year ended December 31, 2007, as filed with the Securities and Exchange Commission on March 10, 2008. In light of these risks, uncertainties and assumptions, the forward-looking events discussed may not occur. In addition, our actual results may vary materially from those anticipated, estimated, suggested or projected. Except as required by law, we do not assume a duty to update forward-looking statements, whether as a result of new information, future events or otherwise. Investors should, however, review additional disclosures made by the Company from time to time in its periodic filings with the Securities and Exchange Commission. Please use caution and do not place reliance on forward-looking statements. All forward-looking statements made by the Company in this document are qualified by these cautionary statements.

Insituform(R), the Insituform(R) logo, Insituform Blue(R), United Pipeline Systems(R) and Clean Water for the World(R) are the registered trademarks of Insituform Technologies, Inc. and its affiliates.

Urges Stockholders to Vote the Company's White Card Today