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                                                                    Exhibit 10.6

                                DEED OF ADHERENCE

DEED is made on 17 December, 2004

BETWEEN

(1) SOUTH EAST WATER LLC whose principal executive office is at 600 Fifth
Avenue, 21st floor, New York, NY 10020 USA (the "Covenantor");

(2) THE PARTIES whose names and addresses are set out in Schedule 1 to this Deed
(the "Shareholders");

(3) MACQUARIE INVESTMENT MANAGEMENT (UK) LIMITED incorporated under the laws of
England whose registered office is at 1 Ropermaker Street London EC2Y 9HD United
Kingdom (the "Adviser");

(4) MACQUARIE LUXEMBOURG WATER S.A.R.L. a company incorporated under the laws of
Luxembourg, whose registered office is at 5, rue guillaume Kroll, -1882
Luxembourg, Grand-Duchy of Luxembourg (the "Company"); and

(5) MACQUARIE INFRASTRUCTURE COMPANY LLC whose principal executive office is at
600 Fifth Avenue, 21st floor, New York, NY 10020 USA (the "Guarantor")

WHEREAS:

(A)  On 30 April, 2004 the Original Investors (defined in Schedule 1 hereto),
     the Adviser and the Company entered into a shareholders' agreement
     governing their relationship as shareholders in the Company and
     establishing the manner in which the affairs of the Company would be
     conducted (the "Shareholders' Agreement").

(B)  On 3 November 2004 Macquarie Global Infrastructure Fund 2 S.A. subscribed
     for 74 shares in the Company and on 4 November 2004 Macquarie Global
     Infrastructure Fund 2 S.A. subscribed for the Euro equivalent of (pound
     sterling) 4,145,525 (less (Euro)1,868.50) A Preferred Equity Certificates
     and (pound sterling)4,107,000 of B Preferred Equity Certificates in the
     Company pursuant to which it signed a deed of adherence on 4 November 2004
     agreeing to become a party to and to be bound by, the Shareholders'
     Agreement.

(C)  The Covenantor wishes to become a party to the Shareholders' Agreement
     immediately upon acquiring certain Securities in the Company and wishes to
     amend the Shareholders' Agreement with the effect that the Covenantor
     becomes a party thereto and, subject to the provisions of this Deed,
     assumes the rights and obligations of a Shareholder under the Shareholders'
     Agreement.

(D)  In order to facilitate the Covenantor becoming a shareholder in the
     Company, the parties have agreed to certain amendments to the Shareholders
     Agreement as set out in clause 3 below.


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(E)  The Covenantor is a member of the Guarantor's Group and the Guarantor has
     agreed to guarantee the obligations of the Covenantor under the
     Shareholders' Agreement.

NOW THIS DEED WITNESSES as follows:

INTERPRETATION

1.   Words and expressions defined in the Shareholders' Agreement shall, unless
     the context otherwise requires, have the same meanings when used in this
     Deed.

ADHERENCE

2.   Subject to the provisions of clause 3 below, the Covenantor hereby
     covenants to and undertakes with each of the Shareholders, the Adviser and
     the Company and with each such other person who may from time to time
     expressly adhere to the Shareholders' Agreement (by way of execution of a
     deed or by way of novation) to be bound by and comply in all respects with
     the Shareholders' Agreement and to assume the benefits of the Shareholders'
     Agreement, as if the Covenantor had executed the Shareholders' Agreement as
     an original party thereto and was named therein as a Coinvestor.

3.   The parties hereby acknowledge and agree to the amendment of the
     Shareholders Agreement as follows, such amendments to be effective as of
     the date hereof:

3.1  The following change being made to clause 1.1:

     The insertion of a new definition as follows "SEW Group" means the Company
     and all of its subsidiary undertakings".

3.2  The following change being made to clause 6:

     The deletion of the word "Each" in the first line and the insertion of the
     words "Upon the request of the Adviser each" in its place.

3.3  The addition of the following clause as a new clause 8.5:

     "PROVISION OF FINANCIAL INFORMATION

     8.5  The Company shall provide the following information to the
          Shareholders:

     (a)  if a Shareholder requests for any specific month, within 30 days of
          the end of that month, management reporting in relation to the
          financial and operational performance of Macquarie Water (UK) Limited
          and its subsidiaries for the respective month; and

     (b)  a quarterly report in relation to the financial performance of
          Macquarie Water (UK) Limited and its subsidiaries, which shall include
          a discounted cash flow valuation; and


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     (c)  consolidated audited annual accounts for the Company under local GAAP
          as soon as reasonably practicable but in any event within 3 months of
          the end of each Financial Year; and

     (d)  if during any quarter the Company has any assets or liabilities other
          than its ownership of debt and equity in Macquarie Water (UK) Limited,
          a quarterly report for that quarter in relation to the financial
          performance of the Company and its subsidiaries, which shall include a
          discounted cash flow valuation."

3.4  The addition of the following clause as a new clause 8.6:

     "MATERIAL CHANGE TO SEW GROUP

     8.6  Upon the authorisation or approval by the Board of the Company (or any
          committee thereof) or by the board (or any committee thereof) of any
          member of the SEW Group, of a course of action which may, or may be
          likely to, result in a material change to (i) the legal structure of
          the SEW Group and/or (ii) any intra-group financing and investment
          arrangements of the SEW Group including, without limitation, (a) any
          change in the balances (excluding the capitalisation of interest) or
          terms of any loans between Macquarie Water (UK) Limited and any entity
          that is a direct or indirect subsidiary of Macquarie Water (UK)
          Limited; (b) the declaration or payment of dividends by any direct
          subsidiary of Macquarie Water (UK) Limited in excess of the cash
          distribution associated with such dividend and (c) any material change
          in the balances (excluding the capitalisation of interest) or terms of
          any loans between members of the SEW Group (a "Material Change") the
          Company shall immediately notify, or in the case of authorisation or
          approval by any member of the SEW Group the Company shall procure that
          such subsidiary immediately notifies, all Shareholders in writing of
          the full details of such Material Change (the "Material Change
          Notice"), and the Company shall use its best endeavours to procure
          that such Material Change Notice is given not less than 45 days prior
          to the Material Change being implemented by the Company or any member
          of the SEW Group."

3.5  The following change being made to clause 20.1:

     The insertion of the words "For the avoidance of doubt this provision shall
     not be applicable so as to require prior approval for any information
     contained in a document prepared to satisfy any reporting obligations
     pursuant to any U.S. federal or state securities laws or regulations or any
     stock exchange requirements." at the end of the paragraph as a new
     sentence.

3.6  The following change being made to paragraph 3.1 of Schedule 3:

     In paragraph 3.1, fourth line, the insertion of the words "at market value"
     after the words "(the "Proposed Transferee")".

RETRANSFER

4.   The Covenantor and the Guarantor hereby undertake to each other Shareholder
     and to the Company that, if the Covenantor ceases or proposes


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     to cease to be a member of the Guarantor's Group the Covenantor will
     forthwith transfer all its interests in any securities in the Company and
     assign its rights and obligations under its Preferred Equity Certificate
     Agreement to the Guarantor or to another member of the Guarantor's Group.

GUARANTEE

5.   The Guarantor hereby irrevocably and unconditionally guarantees the
     performance by the Covenantor of all of its obligations under this Deed and
     the Shareholders' Agreement.

CONTINUING GUARANTEE

6.   The guarantee given in this Deed shall be continuing and shall extend to
     the performance in full of all obligations guaranteed hereunder, regardless
     of any intermediate payment or discharge in whole or in part or performance
     in part.

WAIVER OF DEFENCES

7.   The liabilities and obligations of the Guarantor shall remain in force
     notwithstanding any act, omission, neglect, event or matter whatsoever
     whether or not known to the Guarantor, the Covenantor, the Company, the
     Adviser or the other Shareholders (other than the full performance of all
     obligations guaranteed hereunder) and the foregoing shall apply, without
     limitation, in relation to:

     (a)  anything which would have discharged the Guarantor (wholly or in part)
          whether as surety, co-obligor or otherwise or which would have
          afforded the Guarantor any legal or equitable defence;

     (b)  any winding up, dissolution, reconstruction or reorganisation, legal
          limitation, disability, incapacity or lack of corporate power or
          authority or other circumstances of, or any change in the constitution
          or corporate identity or loss of corporate identity by, the Covenantor
          or any other person; and

     (c)  anything which renders the Covenantor's obligations invalid or
          unenforceable under the Shareholders' Agreement and any defence or
          counterclaim which the Covenantor may be able to assert against any of
          the other Shareholders, the Adviser or the Company.

NO IMPAIRMENT OF GUARANTOR'S OBLIGATIONS

8.   Without limiting clause 6, none of the liabilities or obligations of the
     Guarantor under this Deed shall be impaired by the Company and other
     Shareholders agreeing with the Covenantor to any amendment, variation,
     assignment, novation or departure (however substantial or material) of, to
     or from the Shareholders' Agreement so that any such amendment, variation,
     assignment, novation or departure (including any which may have been made
     before the signing of this Deed) shall, whatever its nature, be binding
     upon the Covenantor in all circumstances, notwithstanding that it may
     increase or otherwise affect the liability of the Guarantor.


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9.   Without limiting clause 6, none of the liabilities or obligations of the
     Guarantor under this Deed shall be impaired by the Company, the Adviser and
     other Shareholders agreeing with the Covenantor any amendment, variation,
     assignment, novation or departure (however substantial or material) of, to
     or from any agreement so that any such amendment, variation, assignment,
     novation or departure (including any which may have been made before the
     signing of this Deed) shall, whatever its nature, be binding upon the
     Guarantor in all circumstances, notwithstanding that it may increase or
     otherwise affect the liability of the Guarantor.

DEMANDS

10.  Demands under this Deed may be made, and the liabilities and obligations of
     the Guarantor under this Deed may be enforced, irrespective of whether any
     demands, steps or proceedings are being or have been made or taken against
     the Covenantor and/or any third party.

RIGHTS SEVERAL

11.  The rights of the Company, the Adviser and each Shareholder under this Deed
     shall be in all respects several and the failure of any one or more of them
     to perform obligations under any agreement shall in no way affect the
     rights of the others of them under or in connection with this Deed. It
     shall not be necessary for the Company, the Adviser or any other
     Shareholder to be joined as an additional party in any proceedings by a
     Shareholder to protect or enforce its rights and interests under this Deed.

INVALIDITY

12.  If any provision of this Deed becomes invalid, illegal or unenforceable in
     any respect under any law, the validity, legality and enforceability of the
     remaining provisions shall not in any way be affected or impaired.

CONTRACTS (RIGHTS OF THIRD PARTIES) ACT 1999

13.  No person who is not a party to this Deed shall have the right to enforce
     any of its terms pursuant to the Contracts (Rights of Third Parties) Act
     1999.

AGENT FOR SERVICE OF PROCESS

14.  The Covenantor shall, unless it is a company incorporated in England and
     Wales, at all times maintain an agent for service of process and any other
     documents in proceedings in England or any other proceedings in connection
     with this Deed. Such agent shall be Macquarie Yorkshire Limited currently
     of Level 30, City Point, 1 Ropemaker Street, London EC2Y 9HD and any writ,
     judgment or other notice of legal process shall be sufficiently served on
     the Covenantor if delivered to such agent at its address for the time
     being. The Covenantor irrevocably undertakes not to revoke the authority of
     the above agent and if, for any reason, the Company requests the Covenantor
     to do so, the Covenantor shall promptly appoint another such agent with an
     address in England and so advise the Company. If following such request,
     the Covenantor fails to appoint another agent, the Company shall be
     entitled to appoint one on behalf of the Covenantor at the expense of the
     Covenantor.


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NOTICES

15.  For the purpose of the Shareholders' Agreement the Covenantor's address for
     notices shall be as follows:

     Address: 600 Fifth Avenue, 21st floor, New York, NY 10020 USA

     Fax No: 212 581 8037

     Addressed for the personal attention of: Peter Stokes

SUBMISSION TO JURISDICTION

16.  Each of the parties agrees that the Courts of England are to have exclusive
     jurisdiction to settle any disputes which may arise in connection with this
     Deed.

GOVERNING LAW

17.  This Deed shall be governed by and construed in accordance with English law
     without prejudice to the mandatory provisions of Luxembourg law.

IN WITNESS whereof this agreement has been executed as a Deed on the date first
above written.

Executed and delivered as a deed by             )
SOUTH EAST WATER LLC                            )  /s/ Peter Stokes
acting by: Peter Stokes,                        )
           Chief Executive Officer              )


Executed and delivered as a deed by             )
MACQUARIE INFRASTRUCTURE COMPANY LLC            )  /s/ Peter Stokes
acting by: Peter Stokes,                        )
           Chief Executive Officer              )


Executed and delivered as a deed by            ) [REDACTED PURSUANT TO
[REDACTED PURSUANT TO CONFIDENTIAL             )  CONFIDENTIAL TREATMENT
TREATMENT REQUEST]                             )  REQUEST]
acting by:

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Executed and delivered as a deed by            )      [REDACTED PURSUANT
[REDACTED PURSUANT TO CONFIDENTIAL             )      TO CONFIDENTIAL
TREATMENT REQUEST]                             )      TREATMENT REQUEST]
acting by:


Executed and delivered as a deed by            )  /s/ James Craig
MEIF LUXEMBOURG HOLDINGS SA                    )  /s/ Bruno Bagnouls
acting by: James Craig and Bruno Bagnouls


Executed and delivered as a deed by            )
MACQUARIE GLOBAL INFRASTRUCTURE FUND 2 S.A.    )  /s/ Simon Chung
acting by Simon Chung and Bruno Bagnouls          /s/ Bruno Bagnouls


Executed and delivered as a deed by            )
MACQUARIE INVESTMENT MANAGEMENT (UK) LIMITED   )  /s/ James Craig
acting by one director and the company         )  /s/ Annabelle Helps
secretary James Craig and Annabelle Helps      )


Executed and delivered as a deed by            )  /s/ James Craig
MACQUARIE LUXEMBOURG WATER S.A.R.L.            )  /s/ Annabelle Helps
acting by: James Craig and Annabelle Helps     )


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                                   SCHEDULE 1

                                THE SHAREHOLDERS

<TABLE>
<CAPTION>
NAME                               ADDRESS
----                               -------
<S>                                <C>
[REDACTED PURSUANT TO              [REDACTED PURSUANT TO CONFIDENTIAL TREATMENT
CONFIDENTIAL TREATMENT             REQUEST]
REQUEST]

[REDACTED PURSUANT TO              [REDACTED PURSUANT TO CONFIDENTIAL TREATMENT
CONFIDENTIAL TREATMENT             REQUEST]
REQUEST]

MEIF Luxembourg Holdings S.A.      a company organized and existing under the
("MEIF" and together with          laws of the Grand Duchy of Luxembourg, having
Alberta and CDP the "Original      its registered office at 398, route d'Esch,
Investors")                        L-1471 Luxembourg

Macquarie Global Infrastructure    Macquarie Global Infrastructure Fund 2 S.A. a
Fund 2 S.A. ("MGIF" and together   company organized and existing under the laws
with the Original Investors the    of the Grand Duchy of Luxembourg, having its
"Shareholders")                    registered office at 5, rue Guillaume Kroll -
                                   BP2501 L-1025 Luxembourg
</TABLE>


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