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                                                                  EXECUTION FORM


                             ECO SOIL SYSTEMS, INC.
                              10740 THORNMINT ROAD
                           SAN DIEGO, CALIFORNIA 92127

                                                   Dated as of November 12, 1999

TO EACH OF THE PURCHASERS LISTED IN
     THE ATTACHED SCHEDULE A

                           AMENDMENT NO. 3 AND WAIVER

Ladies and Gentlemen:

                  Reference is made to the Note and Warrant Purchase
Agreement, dated as of August 25, 1998, as amended by a letter agreement,
dated March 31, 1999, and by Amendment No. 2, dated as of June 30, 1999 (as
so amended, the "Note Agreement"), among Eco Soil Systems, Inc., a Nebraska
corporation (the "Company"), and Albion Alliance Mezzanine Fund, L.P. and
Paribas Capital Funding LLC (collectively, the "Purchasers"). The Purchasers
hold 100% of the Notes outstanding under the Note Agreement. Capitalized
terms used herein without definition have the meanings specified therefor in
the Note Agreement.

                  The Company hereby agrees with the Purchasers as follows:

                  1.       LIMITED WAIVER. The Company represents and
warrants that, except for (a) the Company's non-compliance with sections
10.2(a), (b) and (c) of the Note Agreement for the quarter ended September
30, 1999, (b) any past failure of the Company to have provided monthly
financial reports of the type and within the time period set forth in section
7(e) of the Note Agreement and (c) any past failure of the Company to have
provided notice of its non-compliance with the covenants referred to in this
paragraph 1 within the time period set forth in section 7(h) of the Note
Agreement (the "Existing Defaults"), no condition or event exists which
constitutes an Event of Default or Potential Event of Default. In
consideration of the agreements of the Company set forth hereinafter, the
Purchasers hereby waive the Existing Defaults. This waiver is limited to the
Existing Defaults and may not be construed to extend to any other or
subsequent Events of Default, whether or not disclosed.


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                  2.       AMENDMENT OF SECTION 11. Section 11 of the Note
Agreement is hereby amended to add after subdivision (j) thereof the
following new subdivision (k):

                           "(k) if the Amendment No. 4 Transactions shall not
         have been consummated to the satisfaction of the Purchasers on or prior
         to December 10, 1999;"

                  3.       ADDITIONAL DEFINITION. The following defined term
is hereby added to section 14 of the Note Agreement in the appropriate
alphabetical order:

                           "AMENDMENT NO. 4 TRANSACTIONS:  collectively, the
         following instruments and transactions:

                                    (a) the execution and delivery by the
                  Company of Amendment No. 4 to this Note Agreement, providing
                  for:

                                    (i) the amendment of sections 10.2(a), (b)
                           and (c) of this Agreement for the fiscal quarters
                           ending December 31, 1999, March 31, 2000 and June 30,
                           2000, to replace the ratios set forth therein with a
                           requirement that the Company have EBITDA for such
                           quarters of not less than zero, negative $750,000 and
                           $2,700,000, respectively; and for the fiscal quarter
                           ending September 30, 2000, to amend the ratios set
                           forth therein to be not greater than 4.31 to 1, for
                           section 10.2(a), not greater than 6.15 to 1, for
                           section 10.2(b), and not less than 1.5 to 1, for
                           section 10.2(c);

                                    (ii) the amendment of sections 10.2(d) of
                           this Agreement for the fiscal year 2000 to prohibit
                           the Company from making Capital Expenditures of more
                           than $1,000,000 for such fiscal year;

                                    (iii) the amendment of section 10.1 of this
                           Agreement to provide that the references therein to
                           section 10.2 mean section 10.2 as in effect prior to
                           the amendments contemplated by paragraph (i) above;

                                    (iv) the addition to section 9 of this
                           Agreement of a new provision requiring the


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                           Company to apply the cash proceeds received by the
                           Company or its Subsidiaries after the date of the
                           Amendment No. 4 Transactions as consideration for the
                           issuance of capital stock or securities convertible
                           into or exercisable for capital stock, as follows:
                           (x) the first $7,500,000 of such proceeds to the
                           prepayment of the Notes, without premium, and accrued
                           interest thereon; (y) the next $2,500,000 of such
                           proceeds to be retained by the Company and (z) 50% of
                           all proceeds received after the first $10,000,000 to
                           be applied to the prepayment of the Notes, without
                           premium, and accrued interest thereon; (excluding,
                           however, from any of the proceeds referred to in this
                           paragraph (iv) the first $5,000,000 of the proceeds
                           of the issuance of capital stock to Palladin Group or
                           other investors approved by the Purchasers and
                           amounts received pursuant to the exercise of employee
                           stock options or any outstanding warrants);

                                    (v) the amendment of section 9 to eliminate
                           the premium on voluntary prepayment of the Notes; and

                                    (vi) the payment of the reasonable fees and
                           expenses of counsel for the Purchasers incurred in
                           connection with Amendment No. 3 and 4 to this
                           Agreement;

                  or, in each case, such other amendments as shall be
                  satisfactory to the Purchasers;

                                    (b) the execution and delivery by the
                  Company of an amendment to the Warrants, (i) advancing the
                  commencement of the exercise period of the Warrants from
                  February 25, 2000 to the date of the Amendment No. 4
                  Transactions; (ii) extending the expiration of the exercise
                  period from August 25, 2003 to August 25, 2005 and (iii)
                  adding a provision satisfactory to the Purchasers requiring
                  that, in the event any exercise of Warrants (including the new
                  warrants provided in paragraph (d) below) causes such any
                  Purchaser to violate any provision of applicable law, the
                  Company will either cooperate with such Purchaser


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                  in any efforts by it to dispose of some or all of it shares of
                  Common Stock so as to avoid such violation or use its best
                  efforts to create a non-voting stock to be issued to such
                  Purchaser upon exercise in lieu of the Common Stock;

                                    (c) the issuance to the Purchasers of a
                  number of shares of Common Stock equal to X in the following
                  formula (each Purchaser to receive its PRO RATA share of such
                  number of shares):

                  X = 1,275,000 / Q

                  Q = the lesser of (i) $4.00 and (ii) the average of the
                  closing price for the Common Stock for the ten consecutive
                  trading days immediately prior to the date of the Amendment
                  No. 4 Transactions;

                                    (d) the issuance to the Purchaser of new
                  warrants, having the same exercise price, exercise period and
                  other terms as the Warrants (as amended pursuant to paragraph
                  (b) above), for the purchase of a number of shares of Common
                  Stock equal to Y in the following formula (each Purchaser to
                  receive its PRO RATA share of such number of shares):

                  Y = [262,500 x (8 / Q)] - 262,500

                  Q has the meaning specified in paragraph (c);

                                    (e) the execution and delivery by the
                  Company of an agreement to issue to the Purchasers on March
                  31, 2000, an additional number of shares of Common Stock equal
                  to the greater of 1,000,000 and 5% of the fully-diluted Common
                  Stock on the date of the Amendment No. 4 Transactions (each
                  Purchaser to receive its PRO RATA share of such number of
                  shares) if on such date the Notes shall not have been prepaid;
                  such amount to be reduced in the case of a partial prepayment
                  of the Notes, in proportion to the amount of the Notes
                  prepaid; such share quantities to be adjusted in the event of
                  share splits on or prior to such date;

                                    (f) the execution and delivery by the
                  Company of an agreement conferring on the shares issued
                  pursuant to the foregoing paragraphs (c),


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                  (d) and (e) registration rights comparable to the registration
                  rights currently set forth in the Warrants;

                                    (g) the timely payment on November 25, 1999,
                  of the interest payment due on the Notes on that date; and the
                  payment into an escrow account on or prior to December 10,
                  1999, on terms satisfactory to the Purchasers, of an amount
                  sufficient to pay the interest payment to become due on the
                  Notes on February 25, 2000; and

                                    (h) the delivery by the Company to the
                  Purchaser of a certificate to the effect that, after giving
                  effect to the above transactions, no Event of Default or
                  Potential Event of Default exists."

                  4.       RATIFICATION. Except as amended hereby, all of the
provisions of the Note Agreement shall remain in full force and effect.

                  5.       MISCELLANEOUS. This Amendment and Waiver shall be
binding upon and inure to the benefit of and be enforceable by the respective
successors and assigns of the parties hereto, whether so expressed or not. THIS
AMENDMENT AND WAIVER SHALL BE CONSTRUED AND ENFORCED IN ACCORDANCE WITH AND
GOVERNED BY THE LAW OF THE STATE OF NEW YORK. The headings in this Amendment and
Waiver are for purposes of reference only and shall not limit or otherwise
affect the meaning hereof. This Amendment and Waiver may be executed in any
number of counterparts, each of which shall be an original, but all of which
together shall constitute one instrument.

                    [THIS SPACE IS LEFT BLANK INTENTIONALLY]


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                  If the Purchasers are in agreement with the foregoing, please
sign the form of agreement on the accompanying counterparts of this letter and
return one of the same to the Company, whereupon this letter shall become a
binding agreement between the Purchasers and the Company.

                                         Very truly yours,

                                         ECO SOIL SYSTEMS, INC.

                                         By:_________________________________

The foregoing Amendment is
hereby agreed to as of the
date hereof.

ALBION ALLIANCE MEZZANINE FUND, L.P.

By:  Albion Alliance LLC,
     its General Partner

     By:___________________________
     Name:  Peter C. Gummeson
     Title: Senior Vice President

PARIBAS CAPITAL FUNDING LLC

By: ___________________________
Name:  Jeff Youle
Title: Managing Director


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