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                                                                    EXHIBIT 10.1

                            NOTE MODIFICATION ALLONGE

      The $200,000 Promissory Note (the "NOTE"), dated September 24, 1997, made
by Anthony W. Hooper (the "MAKER") in favor of Insituform Technologies, Inc.
(the "CORPORATION") is hereby amended and modified to change the due date from
the "fifth anniversary" of the date of the Note to the "seventh anniversary" of
the date of the Note.

      If any change in applicable law would require the Note to be repaid prior
to the scheduled due date, then Maker will comply with such law.

      Except as hereby modified, the Note shall remain in full force and effect,
and Maker hereby ratifies the Note as so modified.

      ORAL AGREEMENTS OR COMMITMENTS TO LOAN MONEY, EXTEND CREDIT OR TO FORBEAR
FROM ENFORCING REPAYMENT OF A DEBT, INCLUDING PROMISES TO EXTEND OR RENEW SUCH
DEBT, ARE NOT ENFORCEABLE. TO PROTECT MAKER AND CORPORATION FROM
MISUNDERSTANDING OR DISAPPOINTMENT, ANY AGREEMENTS THEY REACH COVERING SUCH
MATTERS ARE CONTAINED IN THIS WRITING (AND THE NOTE), WHICH ARE THE COMPLETE AND
EXCLUSIVE STATEMENTS OF THE AGREEMENT BETWEEN THEM, EXCEPT AS THEY MAY LATER
AGREE IN WRITING TO MODIFY THEM.

      IN WITNESS WHEREOF, the undersigned have executed this Note Modification
Allonge on July 17, 2002.

                                              /s/ Anthony W. Hooper
                                        ------------------------------------
                                        Anthony W. Hooper

                                        Insituform Technologies, Inc.

                                        By:   /s/ Stephen P. Cortinovis
                                            ------------------------------------
                                            Stephen P. Cortinovis, Chair of the
                                            Compensation Committee of the
                                            Board  of Directors<PAGE>

                                                                    Exhibit 10.2

                                PROMISSORY NOTE

$200,000                                                As of September 24, 1997

     SECTION 1. General. The undersigned, Anthony W. Hooper (the "Maker"),
residing at 3 Wendover, St. Louis, Missouri 63124, for value received, hereby
promises to pay to INSITUFORM TECHNOLOGIES, INC., with offices at 702 Spirit 40
Park Drive, Chesterfield, Missouri 63005 (the "Corporation"), or order, the
principal amount of $200,000 (Two Hundred Thousand Dollars), the principal
balance of which shall be due and payable in full on the fifth anniversary of
the date hereof (subject to mandatory and optional prepayment in whole or in
part in the manner provided in Section 2 hereof), all payments under this Note
to be in such coin or currency of the United States of America as at the time
of payment shall be legal tender therein for the payment of public and private
debts, the principal balance hereof not to accrue interest except in the
circumstances provided under Section 2(b) and Section 4 hereof; all payments
and prepayments under this Note to be made at 702 Spirit 40 Park Drive,
Chesterfield, Missouri 63005, or such other location as shall be specified in
writing by the holder of this Note to the Maker.

     SECTION 2.  Mandatory And Optional Prepayment.

     (a) In the event that the Maker's employment with the Corporation is
terminated by action of the Maker for other than "good reason" (as hereinafter
defined), or by action of the Corporation for "cause" (as hereinafter
defined), the entire outstanding principal balance of this Note shall
immediately become due and payable. For purposes hereof:

     (x) "good reason" shall mean the assignment to the Maker by the Corporation
  of duties inconsistent with the position of chief executive officer, or any
  purported termination by the Corporation of the Maker's employment otherwise
  than for "cause"; and

     (y) "cause" shall mean the willful and continued failure of the Maker
  substantially to perform his duties to the Corporation (other than as a result
  of incapacity due to physical or mental illness) after written demand therefor
  by the Corporation, or the conviction by the Maker of a crime other than
  misdemeanor traffic offenses or of an act of moral turpitude.

     (b) In the event the Maker's employment with the Corporation is terminated
for any reason other than by the Maker without "good reason", or by the
Corporation with "cause", then: (i) the outstanding principal balance of this
Note shall, from the date of termination (the "Termination Date"), accrue
interest at a rate per annum calculated as the Extension Rate (as hereinafter
defined); (ii) the Maker shall, from the Termination Date, pay to the holder of
this Note eleven equal installments, monthly on the same day of each month
thereafter, as if the entire principal balance of this Note outstanding on the
Termination Date, together with interest accrued as aforesaid, were to be
liquidated in equal monthly payments as aforesaid extending over the period
ending 30 years after the

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Termination Date, each such installment hereunder to be applied, first, to
interest so accrued and, then, to the principal balance hereof; and (iii) the
entire outstanding principal balance of this Note, together with interest
accrued hereon, shall be due and payable on the first anniversary of the
Termination Date. For purposes hereof, the "Extension Rate" shall mean one
percent per annum in excess of the interest rate per annum then offered by
NationsBank NA as its prime lending rate.

     (c) The Maker shall have the right at any time to prepay the whole, or any
part, of the unpaid principal amount of this Note, without premium or penalty,
provided that interest, if any, accrued to the date of such prepayment shall be
paid concurrently therewith. Notices of prepayment under this paragraph (c)
shall be given by the Maker by mail and shall be mailed to the holder of this
Note not less than ten days from the date fixed for prepayment. In case this
Note is to be prepaid in part only, such notice shall specify the principal
amount hereof to be prepaid. In the event this Note is to be prepaid in part,
and the provisions of paragraph (b)(ii) immediately preceding obtain, such
prepayment shall be applied in inverse order of maturity to the installments so
required. Upon giving of notice of prepayment as aforesaid, this Note or
portion hereof so specified for prepayment, shall on the prepayment date
specified in such notice become due and payable, and the principal of this Note
or portion hereof so specified for prepayment, together with interest, if any,
accrued thereon, shall then be paid by the Maker.

     SECTION 3.  Events of Default and Remedies.

     3.1  The entire unpaid principal amount of this Note, together with all
accrued interest, if any, hereon, at the option of the holder hereof exercised
by written notice to the Maker, shall forthwith become and be due and payable
if any one or more of the following events (herein called "Events of Default")
shall have occurred (for any reason whatsoever and whether such happening
shall be voluntary or involuntary or come about or be effected by operation of
law or pursuant to or in compliance with any judgment, decree or order of any
court or any order, rule or regulation of any administrative or governmental
body) and be continuing at the time of such notice, that is to say:

     (a) if default shall be made in the due and punctual payment of the
principal of, or any installment on, or any interest accrued on, this Note when
and as the same shall become due and payable, whether at maturity, by
acceleration or otherwise, and such default shall have continued for a period
of 30 days after written notice by the holder of this Note to the Maker;

     (b) if this Note shall cease to be enforceable in accordance with its
terms against the Maker, or the Maker shall so state in writing;

     (c) if the Maker shall:

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          (i)   admit in writing his inability to pay his debts generally as
they become due;

          (ii)  file a petition in bankruptcy or a petition to take advantage of
any insolvency act; or

          (iii) on a petition in bankruptcy filed against him, be adjudicated a
bankrupt.

     3.2  In the case any one or more of the Events of Default specified in
Section 3.1 hereof shall have occurred and be continuing, the holder of this
Note may proceed to protect and enforce its rights either by suit in equity
and/or by action at law, whether for the specific performance of any covenant or
agreement contained in this Note, or the holder of this Note may proceed to
enforce the payment of all sums due upon this Note or to enforce any other legal
or equitable right of the holder of this Note. In the event an Event of Default
shall have occurred and the holder of this Note shall employ attorneys, or incur
other costs and expenses for the collection of payments due or to become due, or
for the enforcement or performance or observance of any obligation or agreement
of the Maker under this Note, the Maker agrees that it will pay to the holder,
on demand, the reasonable fees of such attorney together with all other costs
and expenses incurred by the holder hereof.

     3.3  No remedy herein conferred upon the holder of this Note is intended
to be exclusive of any other remedy and each and every such remedy shall be
cumulative and shall be in addition to every other remedy given hereunder or
now or hereafter existing at law or in equity or by statute or otherwise.

     3.4  No course of dealing between the Maker and the holder of this Note or
any delay on the part of the holder hereof in exercising any rights hereunder
shall operate as a waiver of any rights of the holder hereof.

     SECTION 4.  Default Interest.

     4.1 While an Event of Default is continuing, the Maker shall pay interest
on the outstanding principal balance of this Note at a rate per annum which is
equal to twelve percent (12%), such interest to be payable in arrears on the
first day of each calendar month for the immediately preceding calendar month,
commencing with the first such day following the date of the Event of Default,
until the principal amount of this Note is paid in full.

     4.2  Notwithstanding anything to the contrary contained in this Note, the
Maker shall not be obligated to pay, and the holder of this Note shall not
charge, reserve, collect or receive interest (which shall be calculated as the
aggregate of all charges which constitute interest under applicable law) in
excess of the maximum non-usurious interest rate, as in effect from time to
time, which may be charged, reserved, received or collected by the holder in
connection with this Note. During any period of time in which the interest rates
specified herein exceed the maximum rate as aforesaid,

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interest shall accrue and be payable at such maximum rate; provided, however,
that if the interest rate payable hereunder declines below the maximum rate as
aforesaid, interest shall continue to accrue and be payable at such maximum
rate until the interest that has been paid by the Maker hereunder equals the
amount of interest that would have been paid if interest had at all times
accrued and been payable at the applicable interest rate specified in this
Note. In the event that the holder of this Note shall collect from the Maker
any amount which is deemed to constitute interest at a rate in excess of the
maximum rate as aforesaid, all such excess amounts shall be credited to the
payment of outstanding principal advanced to the Maker.

          Section 5.     Captions. Captions and section titles contained herein
are inserted as a matter of convenience and for reference only and are not
intended to define, limit, extend or describe the scope of this Note or the
intent of any provision hereof.

          Section 6.     Severability. In the event that one or more of the
provisions of this Note shall for any reason be held to be invalid, illegal or
unenforceable in any respect, such invalidity, illegality or unenforceability
shall not affect any other provisions of this Note, but this Note shall be
construed as if such invalid, illegal or unenforceable provision had never been
contained herein.

          Section 7.     Governing Law. This Note shall be governed by and
construed in accordance with the laws of the State of Missouri applicable to
agreements made and to be performed entirely within such state.

          Section 8.     Statutory Notice. The following notice is given
pursuant to applicable statute; nothing contained in such notice shall be deemed
to limit or modify the terms of this Note:

     ORAL AGREEMENT OR COMMITMENTS TO LOAN MONEY, EXTEND CREDIT OR TO FOREBEAR
     FROM ENFORCING REPAYMENT OF A DEBT, INCLUDING PROMISES TO EXTEND OR RENEW
     SUCH DEBT OR TO AMEND OR MODIFY THE TERMS OF SUCH DEBT, ARE NOT
     ENFORCEABLE. TO PROTECT THE MAKER AND THE HOLDER OF THIS NOTE FROM
     MISUNDERSTANDING OR DISAPPOINTMENT, ANY AGREEMENTS REACHED BY THE MAKER AND
     THE HOLDER HEREOF COVERING ANY OF THE FOREGOING SUCH MATTERS OR OTHERWISE
     ARE CONTAINED EXCLUSIVELY AND SOLELY IN THIS NOTE, WHICH NOTE IS A COMPLETE
     AND EXCLUSIVE STATEMENT OF THE AGREEMENTS BETWEEN THE MAKER AND THE HOLDER
     HEREOF WITH RESPECT TO THE SUBJECT MATTER HEREOF, EXCEPT AS THE MAKER AND
     THE HOLDER MAY LATER AGREE IN WRITING TO MODIFY THEM.

          IN WITNESS WHEREOF, the undersigned has executed this Note as of the
date first-above written.

                             /s/ Anthony W. Hooper
                             ----------------------
                             Anthony W. Hooper

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