EXHIBIT 32.2 CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002 In connection with the quarterly report of Insituform Technologies, Inc. (the "COMPANY") on Form 10-Q for the quarter ended September 30, 2004 as filed with the Securities and Exchange Commission on the date hereof (the "FORM 10-Q"), I, Christian G. Farman, Vice President and Chief Financial Officer of the Company, hereby certify, as of the date hereof, that: (1) the Form 10-Q fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and (2) information contained in the Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of the Company. Dated: November 9, 2004 /s/ Christian G. Farman -------------------------------------------- Christian G. Farman Vice President and Chief Financial Officer