UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                  SCHEDULE 13G

                    Under the Securities Exchange Act of 1934

                               (Amendment No. 1 )*

                          American States Water Company
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                                (Name of Issuer)

                                  Common Stock
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                         (Title of Class of Securities)

                                    029899101
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                                 (CUSIP Number)

                                December 31, 2007
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             (Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

      [X]   Rule 13d-1(b)

      [ ]   Rule 13d-1(c)

      [ ]   Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).



                                  SCHEDULE 13G

CUSIP No. 029899101

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      1.    Names of Reporting Persons. I.R.S. Identification Nos. of above
            persons (entities only).
            Invesco Ltd.
                  Invesco National Trust Company
                  PowerShares Capital Management LLC

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      2.    Check the Appropriate Box if a Member of a Group (see Instructions)
            (a)
            (b)

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      3.    SEC Use Only _______________________________________________________

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      4.    Citizenship or Place of Organization
            Invesco Ltd. - Bermuda
                  Invesco National Trust Company - US
                  PowerShares Capital Management LLC - US

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                       5.      Sole Voting Power: 713,076 Such
                               shares are held by the following
                               entities in the respective amounts
                               listed:

                                  PowerShares Capital Management LLC - 713,076

Number of Shares    ------------------------------------------------------------
Beneficially Owned
by Each Reporting      6.      Shared Voting Power -0-
Person With
                    ------------------------------------------------------------

                       7.      Sole Dispositive Power: 715,551 Such
                               shares are held by the following
                               entities in the respective amounts
                               listed:
                                  Invesco National Trust Company - 2,475
                                  PowerShares Capital Management LLC - 713,076

                    ------------------------------------------------------------

                       8.      Shared Dispositive Power -0-

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      9.    Aggregate Amount Beneficially Owned by Each Reporting Person:

            715,551

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      10.   Check if the Aggregate Amount in Row (9) Excludes Certain Shares
            (See Instructions) N/A

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      11.   Percent of Class Represented by Amount in Row (9) 4.16%

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      12.   Type of Reporting Person (See Instructions) IA, HC. See Items 2 and
            3 of this statement.



                                  SCHEDULE 13G

Item 1(a)   Name of Issuer:

               American States Water Company

Item 1(b)   Address of Issuer's Principal Executive Offices:

                  630 East Foothill Boulevard
                  San Dimas, CA 91773
                  United States

Item 2(a)   Name of Person Filing:

            Invesco Ltd.

            In accordance with Securities and Exchange Commission Release No.
            34-39538 (January 12, 1998), this statement on Schedule 13G or
            amendment thereto is being filed by Invesco Ltd. ("Invesco"), a
            Bermuda Company, on behalf of itself and its subsidiaries listed in
            Item 4 of the cover of this statement. Invesco through such
            subsidiaries provides investment management services to
            institutional and individual investors worldwide.

            Executive officers and directors of Invesco or its subsidiaries may
            beneficially own shares of the securities of the issuer to which
            this statement relates (the "Shares"), and such Shares are not
            reported in this statement. Invesco and its subsidiaries disclaim
            beneficial ownership of Shares beneficially owned by any of their
            executive officers and directors. Each of Invesco's direct and
            indirect subsidiaries also disclaim beneficial ownership of Shares
            beneficially owned by Invesco and any other subsidiary.

Item 2(b)   Address of Principal Business Office:

            1360 Peachtree Street NE
            Atlanta, GA 30309
            United States

Item 2(c)   Citizenship:

            See the response to Item 2(a) of this statement.

Item 2(d)   Title of Class of Securities:

            Common Stock, .01 par value per share

Item 2(e)   CUSIP Number:

            029899101

Item 3      If this statement is filed pursuant to ss240.13d-1(b) or
            240.13d-2(b) or (c), check whether the person filing is a:

    (e) [x] An investment adviser in accordance with section 240.13d-1(b)
           (1)(ii)(E)

    (g) [x] A parent holding company or control person in accordance with
            section 240.13d-1(b)(1)(ii)(G)

            As noted in Item 2 above, Invesco is making this filing on behalf of
            its subsidiaries listed herein. Each of these entities is either an
            investment adviser registered with the United States Securities and
            Exchange Commission under Section 203 of the Investment Advisers Act
            of 1940, as amended, or under similar laws of other jurisdictions.
            Invesco is a holding company.



Item 4      Ownership:

            Please see responses to Items 5-8 on the cover of this statement,
            which are incorporated herein by reference.

Item 5      Ownership of Five Percent or Less of a Class:

            If this statement is being filed to report the fact that as of the
            date hereof the reporting person has ceased to be the beneficial
            owner of more than five percent of the class of securities, check
            the following

            [x]

Item 6      Ownership of More than Five Percent on Behalf of Another Person:

            N/A

Item  7     Identification and Classification of the Subsidiary Which Acquired
            the Security Being reported on By the Parent Holding Company:

            Please see Item 3 of this statement, which is incorporated herein by
            reference.

Item 8      Identification and Classification of Members of the Group:

            N/A

Item 9      Notice of Dissolution of a Group:

            N/A

Item 10     Certification:

            By signing below I certify that, to the best of my knowledge and
            belief, the securities referred to above were acquired and are held
            in the ordinary course of business and were not acquired and are not
            held for the purpose of or with the effect of changing or
            influencing the control of the issuer of the securities and were not
            acquired and are not held in connection with or as a participant in
            any transaction having that purpose or effect.

            Signature:

            After reasonable inquiry and to the best of my knowledge and belief,
            I certify that the information set forth in this statement is true,
            complete and correct.

                                             02/09/2008
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                                                Date

                                  Invesco Ltd.

                                  By: /s/ Lisa Brinkley
                                      ------------------------------------------
                                  Lisa Brinkley
                                  Global Compliance Director