EXHIBIT 23.1 CONSENT OF INDEPENDENT ACCOUNTANTS We hereby consent to the incorporation by reference in this Post-Effective Amendment No. 1 to the Registration Statement on Form S-8 of our report dated March 12, 2004 relating to the consolidated financial statements of Insituform Technologies, Inc., which appears in the Company's Annual Report on Form 10-K for the year ended December 31, 2003. /s/ PricewaterhouseCoopers LLP PricewaterhouseCoopers LLP St. Louis, Missouri August 27, 2004