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                                                                     Exhibit 4.3

                   AGREEMENT OF SUBSTITUTION AND AMENDMENT OF
                         COMMON SHARES RIGHTS AGREEMENT


         This Agreement of Substitution and Amendment is entered into as of
January 15, 2002, by and between Pennichuck Corporation, a New Hampshire
corporation (the "Company") and American Stock Transfer and Trust Company, a New
York banking corporation ("AST").

                                    RECITALS

A.       On or about April 20, 2000, the Company entered into a Rights
         Agreement, as subsequently amended (the "Rights Agreement") with Fleet
         National Bank as rights agent.

B.       On or about October 10, 2001, EquiServe Trust Company, N.A., an
         affiliate of Fleet National Bank, was appointed as successor rights
         agent under the Rights Agreement (the "Predecessor Agent").

C.       The Company wishes to remove the Predecessor Agent and substitute AST
         as rights agent pursuant to Section 21 of the Rights Agreement.

D.       The Company has given the Predecessor Agent proper notice of removal
         of the Predecessor Agent as rights agent.

                                   AGREEMENT

         NOW THEREFORE, in consideration of the foregoing and of other
consideration, the sufficiency of which is hereby acknowledged, the parties
agree as follows:

1.       The Company hereby appoints AST as rights agent pursuant to Section 21
         of the Rights Agreement, to serve in that capacity for the
         consideration and subject to all of the terms and conditions of the
         Rights Agreement.

2.       AST hereby accepts the appointment as rights agent pursuant to Section
         21 of the Rights Agreement and agrees to serve in that capacity for the
         consideration and subject to all of the terms and conditions of the
         Rights Agreement.

3.       From and after the effective date hereof, each and every reference in
         the Rights Agreement to a "Rights Agent" shall be deemed to be a
         reference to AST.

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4.       Section 3(c) of the Rights Agreement is amended by striking the form of
         the legend contained in said section and substituting the following in
         lieu thereof:

                  This certificate also evidences and entitles the holder hereof
                  to certain Rights as set forth in a Rights Agreement between
                  Pennichuck Corporation and American Stock Transfer & Trust
                  Company as Rights Agent, dated as of April 20, 2000, as
                  amended (the "Rights Agreement"), the terms of which are
                  hereby incorporated herein by reference and a copy of which is
                  on file at the principal executive offices of Pennichuck
                  Corporation. Under certain circumstances, as set forth in the
                  Rights Agreement, such Rights will be evidenced by separate
                  certificates and will no longer be evidenced by this
                  certificate. Pennichuck Corporation will mail to the holder of
                  this certificate a copy of the Rights Agreement without charge
                  after a receipt of a written request therefor. Under certain
                  circumstances, Rights that are or were acquired or
                  beneficially owned by Acquiring Persons (as defined in the
                  Rights Agreement) may become null and void.

5.       Section 26 of the Rights Agreement is amended to provide that notices
         or demands shall be addressed as follows (until another address is
         filed):

         If to the Company:             Pennichuck Corporation
                                        4 Water Street, P.O. Box 448
                                        Nashua, New Hampshire 03061-0448
                                        Attention: President

         with a copy to:                Gallagher, Callahan & Gartrell, P.A.
                                        214 North Main Street, P.O. Box 1415
                                        Concord, New Hampshire 03302-1415

         If to AST:                     American Stock Transfer & Trust Company
                                        59 Maiden Lane
                                        New York, NY 10038
                                        Attention: Shareholder Services Division

6.       Except as expressly modified herein, the Rights Agreement shall remain
         in full force and effect.

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7.       This Agreement of Substitution and Amendment may be executed in one or
         more counterparts, each of which shall together constitute one and the
         same document.

         IN WITNESS WHEREOF, the parties have caused this Agreement to be duly
executed as of the date indicated above.

                                        PENNICHUCK CORPORATION

                                        By: /s/ Charles J. Staab
                                            -----------------------------------
                                            Charles J. Staab
                                            Vice President, Treasurer and
                                            Chief Financial Officer

                                        AMERICAN STOCK TRANSFER & TRUST COMPANY

                                        By: /s/ Herbert J. Lemmer
                                            -----------------------------------
                                            Herbert J. Lemmer
                                            Vice President