SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                 SCHEDULE 13D/A
                    Under the Securities Exchange Act of 1934
                               (Amendment No. 25)

                              Quanta Services, Inc.
                              ---------------------
                                (Name of Issuer)

                        Common Stock, $0.00001 par value
                        --------------------------------
                         (Title of Class of Securities)

                                    74762E102
                                    ---------
                                 (CUSIP Number)

       Leslie J. Parrette, Jr., Senior Vice President, General Counsel and
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                              Corporate Secretary
                              -------------------
                Aquila, Inc. (formerly, UtiliCorp United Inc.)
                              ---------------------
        20 West Ninth Street, Kansas City, Missouri 64105 (816) 421-6600
        ----------------------------------------------------------------
                  (Name, Address and Telephone Number of Person
                Authorized to Receive Notices and Communications)

                                  March 26, 2002
             (Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report
the acquisition that is the subject of this Schedule 13D, and is filing this
schedule because of Rule 13d-1(e), 13d-1(f), or 13d-1(g), check the following
box. / /

NOTE: Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See Section 240.13d-7(b) for
other parties to whom copies are to be sent.

The information required on 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).



                               CUSIP No. 74762E102
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     1    NAMES OF REPORTING PERSONS
          I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only)

          Aquila, Inc. (formerly, UtiliCorp United Inc.) #440541877
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     2    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See Instructions)
          (a)
          (b)  X
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     3    SEC USE ONLY

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     4    SOURCE OF FUNDS (See Instructions)

          WC, BK
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     5    CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
          ITEMS 2(d) or 2(e)

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     6    CITIZENSHIP OR PLACE OR ORGANIZATION

          Delaware
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  NUMBER OF SHARES            7    SOLE VOTING POWER
 BENEFICIALLY OWNED
 BY EACH REPORTING                 29,243,179
    PERSON WITH
                              --------------------------------------------------
                              8    SHARED VOTING POWER
                                   None*
                              --------------------------------------------------
                              9    SOLE DISPOSITIVE POWER
                                   29,243,179
                              --------------------------------------------------
                              10   SHARED DISPOSITIVE POWER
                                   None
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     11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
          29,243,179
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     12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES
          (See Instructions)
          X
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     13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
          38.06%**
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     14   TYPE OF REPORTING PERSON (See Instructions)
          CO
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*    This representation is qualified by the fact that, as described in Item 4
     of the Schedule 13D, Aquila has the ability to vote or direct the vote
     of the shares subject to the Stockholder's Voting Agreements only in two
     limited, tax-related circumstances. Aquila expressly disclaims beneficial
     ownership to any shares of Common Stock that are subject to the
     Stockholder's Voting Agreements.

**   The percentage reflected in row 13 above is obtained by using 76,829,934
     shares as the denominator (in accordance with Rule 13d-3(d)(1)(i)(B)). This
     denominator includes: (a) 59,605,129 shares of Issuer's issued and
     outstanding Common Stock (as indicated in Issuer's Form 10-Q filed on
     November 14, 2001), and (b) 17,224,805 shares of Common Stock into which
     Issuer's Convertible Preferred Stock held by Aquila is convertible.


                                       2


     Also note that the percentage of Common Stock owned by Aquila on a
     partially diluted basis is approximately 36.04%. This percentage is
     obtained by using 81,145,385 shares as the denominator, which includes (a)
     the 76,829,934 shares discussed in the previous paragraph, (b) 1,152,055
     shares of Limited Vote Common Stock (as indicated in Issuer's Form 10-Q
     filed on November 14, 2001), and (c) 3,163,396 shares of Common Stock into
     which the Issuer's Convertible Subordinated Notes can be converted.
     Aquila's ownership can be further diluted by (x) other classes of
     Issuer's securities that can be converted into Common Stock and (y) shares
     of Common Stock issuable under Issuer's Stock Option Plan.


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                               AMENDMENT NO. 25 TO
                            STATEMENT ON SCHEDULE 13D

INTRODUCTION

     All information herein with respect to Aquila, Inc. (formerly known as
UtiliCorp United Inc.), a Delaware corporation ("Aquila"), and the common
stock, par value $0.00001 per share (the "Common Stock"), of Quanta
Services, Inc., a Delaware corporation ("Issuer" or "Quanta"), is correct to
the best knowledge and belief of Aquila. The Schedule 13D originally filed on
October 4, 1999 on behalf of Aquila and twenty-three amendments thereto filed
on October 8, 1999, October 14, 1999, October 20, 1999, October 26, 1999,
November 9, 1999, January 13, 2000, April 27, 2000, May 25, 2000, June 20,
2000, July 17, 2000, May 23, 2001, October 1, 2001, October 4, 2001, October
11, 2001, October 19, 2001, October 30, 2001, November 13, 2001, November 28,
2001, February 8, 2002, February 25, 2002, March 7, 2002, March 12, 2002 and
March 21, 2002 respectively, on behalf of Aquila are incorporated by reference
and amended as follows.

ITEM 4. PURPOSE OF TRANSACTION.

     On March 12, 2002 and March 21, 2002, Aquila filed Amendments 23 and 24
to Schedule 13D, respectively (the "Amendments"). Due to a filing error, the
second page of each Amendment, which contains the information required by the
Instructions to Schedule 13D, was inadvertently omitted. Exhibit 99.1
attached hereto contains the missing page to each of the Amendments. Such
page does not reflect any changes to the information previously provided in
Amendment 22.

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ITEM 7.           MATERIAL TO BE FILED AS EXHIBITS.

Cover Page for Amendments 23 and 24 to Schedule 13D.


                                       5



                                    SIGNATURE

     After reasonable inquiry and to the best of the undersigned's knowledge and
belief, the undersigned hereby certifies that the information set forth in this
statement is true, complete and correct.

Dated: March 26, 2002                Aquila, Inc.

                                        By:       /s/ Leslie J. Parrette, Jr.
                                        Name:     Leslie J. Parrette, Jr.
                                        Title:    Senior Vice President,
                                                  General Counsel and Corporate
                                                  Secretary


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