Exhibit 23.1 - Consent of Independent accounting firm

We hereby consent to the incorporation by reference in this Registration Statement on Form S-8 of our report dated February 22, 2006, relating to the financial statements, management’s assessment of the effectiveness of internal control over financial reporting and the effectiveness of internal control over financial reporting, of Insituform Technologies, Inc., which appears in Insituform Technologies Inc.’s Annual Report on Form 10-K for the year ended December 31, 2005.