<PAGE>


                  FIRST AMENDMENT TO REVOLVING CREDIT AGREEMENT

              THIS FIRST AMENDMENT TO REVOLVING CREDIT AGREEMENT (this
"AMENDMENT") is made as of November 10, 1999, by and among ERP OPERATING LIMITED
PARTNERSHIP (the "BORROWER"), BANK OF AMERICA, NATIONAL ASSOCIATION, as
Administrative Agent (the "ADMINISTRATIVE AGENT"), THE CHASE MANHATTAN BANK, as
Syndication Agent, MORGAN GUARANTY TRUST COMPANY OF NEW YORK, as Documentation
Agent, and the BANKS listed on the signature pages hereof.

                              W I T N E S S E T H:

              WHEREAS, the Borrower and the Banks have entered into the
Revolving Credit Agreement, dated as of August 12, 1999 (the "CREDIT
AGREEMENT"); and

              WHEREAS, the parties desire to modify the Credit Agreement upon
the terms and conditions set forth herein.

              NOW THEREFORE, for good and valuable consideration, the receipt
and sufficiency of which are hereby acknowledged, the parties do hereby agree as
follows:

              1. DEFINITIONS. All capitalized terms not otherwise defined herein
shall have the meanings ascribed to them in the Credit Agreement.


<PAGE>


              2. LOAN DOCUMENTS. The definition "Loan Documents" is hereby
amended by adding the following after "and the Letter of Credit Documents": "and
any Guaranty".

              3. QUALIFYING UNENCUMBERED PROPERTY. The definition "Qualifying
Unencumbered Property" is hereby amended by adding the following after the last
sentence thereof:

                  Notwithstanding the foregoing, for the purposes of this
                  definition, a Property shall be deemed to be wholly-owned by
                  Borrower if such Property shall be owned by a Down REIT (as
                  hereinafter defined) or a wholly-owned Subsidiary of such Down
                  REIT. The term "Down REIT" shall mean a limited liability
                  company or limited partnership in which the only interest in
                  such Down REIT not owned (directly or indirectly) by Borrower
                  shall be preference interests or preference units,
                  respectively, and which limited liability company or limited
                  partnership, as the case may be (collectively, a "GUARANTOR"),
                  has executed and delivered to the Administrative Agent, on
                  behalf of the Banks, (i) a Guaranty of Payment in the form
                  attached hereto as EXHIBIT A (a "GUARANTY"), (ii) all
                  documents reasonably requested by the Administrative Agent
                  relating to the existence of such Down REIT, and the authority
                  for and validity of the Guaranty, including, without
                  limitation, the organizational documents of such Down REIT,
                  modified or supplemented prior to the date of such Guaranty,
                  each certified to be true, correct and complete by such Down
                  REIT, not more than ten (10) days prior to the date of such
                  Guaranty, together with a good standing certificate from the
                  Secretary of State (or the equivalent thereof) of the State of
                  formation of such Down REIT, to be dated not more than ten
                  (10) days prior to the date


                                        2

<PAGE>


                  of such Guaranty, as well as authorizing resolutions in
                  respect of the Guaranty, and (iii) an opinion of counsel with
                  respect to such Down REIT and Guaranty, in form and substance
                  reasonably acceptable to the Administrative Agent, with
                  respect to due organization, existence, good standing and
                  authority, and validity and enforceability of the Guaranty. In
                  addition, for purposes of this definition, a Guaranty shall
                  not be deemed to constitute Unsecured Debt of the applicable
                  Down REIT.

              4. LETTERS OF CREDIT. Sections 2.16(b) and (d) of the Credit
Agreement are hereby deleted.

              5. PERMITTED HOLDINGS. For purposes of calculating Multifamily
Residential Property Partnership Interests pursuant to Section 5.8(j) of the
Credit Agreement, a Down REIT (or a wholly-owned Subsidiary thereof) shall be
deemed to be wholly-owned by Borrower.

              6. GUARANTY. (i) Notwithstanding any other provision of the Credit
Agreement or any other Loan Document to the contrary, the Administrative Agent,
the Banks and Designated Lenders agree with Borrower that any funds, claims, or
distributions actually received by the Administrative Agent for the account of
any Bank or Designated Lender as a result of the enforcement of, or pursuant to,
any Guaranty, net of the Administrative Agent's and the Banks' expenses of
collection thereof (such net amount, "GUARANTY PROCEEDS"), shall be made
available for distribution equally and ratably (in proportion to the aggregate
amount of principal, interest and other



                                       3

<PAGE>


amounts then owed in respect of the Obligations or of an issuance of Public Debt
(as defined below), as the case may be) among the Administrative Agent, the
Banks and the Designated Lenders and the trustee or trustees of any Unsecured
Debt, not subordinated to the Obligations (or to the holders thereof), issued by
Borrower, before or after the Effective Date, in offerings registered under the
Securities Act of 1933, as amended, or in transactions exempt from registration
pursuant to rule 144A or Regulation 8 thereunder or listed on non-U.S.
securities exchanges ("PUBLIC DEBT"), and the Administrative Agent is hereby
authorized, by Borrower, by each Bank (on its own behalf and on behalf of its
Designated Lender, if any) and by each Guarantor by its execution and delivery
of a Guaranty, to make such Guaranty Proceeds so available. No Bank or
Designated Lender shall have any interest in any amount paid over by the
Administrative Agent to the trustee or trustees in respect of any Public Debt
(or to the holders thereof) pursuant to the foregoing authorization. This
Section 6 shall apply solely to Guaranty Proceeds, and not to any payments,
funds, claims or distributions received by the Administrative Agent, any Bank or
Designated Lender directly or indirectly from Borrower or any other Person other
than from a Guarantor pursuant to a Guaranty. Borrower is aware of the terms of
the


                                       4

<PAGE>


Guaranties, and specifically understands and agrees with the Administrative
Agent, the Banks and the Designated Lenders that, to the extent Guaranty
Proceeds are distributed to holders of Public Debt or their respective trustees,
such Guarantor has agreed that the Obligations will not be deemed reduced by any
such distributions and such Guarantor shall continue to make payments pursuant
to its Guaranty until such time as the Obligations have been paid in full (and
the Commitments have been terminated and any Letter of Credit returned), after
taking into account any such distributions of Guaranty Proceeds in respect of
Indebtedness other than the Obligations.

              (ii) Nothing contained herein shall be deemed (A) to limit,
    modify, or alter the rights of the Administrative Agent, the Banks and the
    Designated Lenders under any Guaranty, (b) to subordinate the Obligations to
    any Public Debt, or (C) to give any holder of Public Debt (or any trustee
    for such holder) any rights of subrogation.

              (iii) This Amendment and all Guaranties, are for the sole benefit
    of the Administrative Agent, the Banks and the Designated Lenders and their
    respective successors and assigns. Nothing contained herein or in any
    Guaranty shall be deemed for the benefit of any holder of Public Debt, or
    any trustee for such holder; nor shall


                                       5

<PAGE>


    anything contained herein or therein be construed to impose on the
    Administrative Agent, any Bank or any Designated Lender any fiduciary
    duties, obligations or responsibilities to the holders of any Public Debt or
    their trustees (including, but not limited to, any duty to pursue any
    Guarantor for payment under its Guaranty).

              7. EFFECTIVE DATE. This Amendment shall become effective when each
of the following conditions is satisfied (or waived by the Required Banks) (the
date such conditions are satisfied or waived being deemed the "EFFECTIVE DATE"):

(a)              the Borrower shall have executed and delivered to the
                 Administrative Agent a duly executed original of this
                 Amendment;

(b)              the Required Banks shall have executed and delivered to the
                 Administrative Agent a duly executed original of this
                 Amendment;

(c)              the Administrative Agent shall have received all documents the
                 Administrative Agent may reasonably request relating to the
                 existence of the Borrower, the authority for and the validity
                 of this Amendment, and the other documents executed in


                                       6

<PAGE>


                 connection therewith, and any other matters relevant hereto,
                 all in form and substance reasonably satisfactory to the
                 Administrative Agent. Such documentation shall include, without
                 limitation, the organizational documents of the Borrower, as
                 amended, modified or supplemented prior to the Effective Date,
                 each certified to be true, correct and complete by an officer
                 of the Borrower, as of a date not more than twenty (20) days
                 prior to the Effective Date, together with a good standing
                 certificate from the Secretary of State (or the equivalent
                 thereof) of the State of Maryland, to be dated not more than
                 twenty (20) days prior to the Effective Date;

(d)              the Administrative Agent shall have received all certificates,
                 agreements and other documents and papers referred to in this
                 Amendment, unless otherwise specified, in sufficient
                 counterparts, satisfactory in form and substance to the
                 Administrative Agent in its reasonable discretion;

(e)              the Borrower shall have taken all actions required to authorize
                 the execution and delivery of this Amendment and the
                 performance hereof by the Borrower;



                                       7

<PAGE>


(f)              the Administrative Agent shall have received the reasonable
                 fees and expenses accrued through the Effective Date of
                 Skadden, Arps, Slate, Meagher & Flom LLP, together with any
                 other fees or expenses of the Administrative Agent;

(g)              the representations and warranties of the Borrower contained in
                 the Credit Agreement, as amended hereby, shall be true and
                 correct in all material respects on and as of the Effective
                 Date; and

(h)              receipt by the Administrative Agent and the Banks of a
                 certificate of an officer of the Borrower certifying that, on a
                 pro forma basis, the Borrower is in compliance with the
                 requirements of Section 5.8 of the Credit Agreement.

              8. ENTIRE AGREEMENT. This Amendment constitutes the entire and
final agreement among the parties hereto with respect to the subject matter
hereof and there are no other agreements, understandings, undertakings,
representations or warranties among the parties hereto with respect to the
subject matter hereof except as set forth herein.

              9. GOVERNING LAW. This Amendment shall be governed by, and
construed in accordance with, the law of the State of Illinois.


                                       8

<PAGE>


              10. COUNTERPARTS. This Amendment may be executed in any number of
counterparts, all of which taken together shall constitute one and the same
agreement, and any of the parties hereto may execute this Amendment by signing
any such counterpart.

              11. HEADINGS, ETC. Section or other headings contained in this
Amendment are for reference purposes only and shall not in any way affect the
meaning or interpretation of this Amendment.

              12. NO FURTHER MODIFICATIONS. Except as modified herein, all of
the terms and conditions of the Credit Agreement, as modified hereby shall
remain in full force and effect and, as modified hereby, the Borrower confirms
and ratifies all of the terms, covenants and conditions of the Credit Agreement
in all respects.


                                       9

<PAGE>


              IN WITNESS WHEREOF, the parties hereto have caused this Amendment
to be duly executed by their respective authorized officers as of the day and
year first above written.


BORROWER:                              ERP OPERATING LIMITED PARTNERSHIP

                                       By: Equity Residential
                                           Properties Trust

                                       By: /s/ David J. Neithercut
                                           -------------------------------
                                           Name:  David J. Neithercut
                                           Title: Executive Vice President
                                                   Chief Financial Officer


                                       10

<PAGE>


                                       BANK OF AMERICA, NATIONAL ASSOCIATION, as
                                       Administrative Agent, as Swingline Lender
                                       and as a Bank

                                       By: /s/ Megan McBride
                                           -------------------------
                                           Name: Megan McBride
                                           Title:  Vice President


                                       11

<PAGE>


                                       THE CHASE MANHATTAN BANK, as Syndication
                                       Agent and as a Bank

                                       By: /s/ Marc E. Costantino
                                           -------------------------
                                           Name:  Marc E. Costantino
                                           Title: Vice President


                                       12

<PAGE>


                                       MORGAN GUARANTY TRUST COMPANY OF NEW
                                       YORK, as Documentation Agent and as a
                                       Bank

                                       By: /S/ R. DAVID STONE
                                          ---------------------------
                                          Name:  R. David Stone
                                          Title: Associate



                                       13

<PAGE>


                                       BANK ONE, NA (f/k/a The First National
                                       Bank of Chicago), as a Co-Arranger and as
                                       a Bank

                                       By: /s/ Lynn Braun
                                          -------------------------------
                                          Name:  Lynn Braun
                                          Title: Vice President


                                       14

<PAGE>


                                       FIRST UNION NATIONAL BANK, as a
                                       Co-Arranger and as a Bank

                                       By: /s/ Rex E. Rudy
                                           ----------------------
                                           Name:  Rex E. Rudy
                                           Title: Vice President


                                       15
<PAGE>


                                       BAYERISCHE LANDESBANK, CAYMAN ISLANDS
                                       BRANCH, as Managing Agent and as a Bank

                                       By: /s/ John A. Wain
                                           ---------------------------
                                           Name:  John A. Wain
                                           Title: First Vice President

                                       By: /s/ Alexander Kohnert
                                           -----------------------------
                                           Name:  Alexander Kohnert
                                           Title: First Vice President


                                       16

<PAGE>


                                       COMMERZBANK AKTIENGESELLSCHAFT, as
                                       Managing Agent and as a Bank

                                       By: /s/ Ralph C. Marra
                                           ------------------------
                                           Name:  Ralph C. Marra
                                           Title: Vice President

                                       By: /s/ David Buettner
                                           -------------------------
                                           Name:  David Buettner
                                           Title: Assistant Treasurer


                                       17

<PAGE>


                                       PNC BANK, NATIONAL ASSOCIATION, as
                                       Managing Agent and as a Bank

                                       By: /s/ Michael E. Smith
                                           ---------------------------
                                           Name:  Michael E. Smith
                                           Title: Vice President


                                       18

<PAGE>


                                       COMERICA BANK, as Co-Agent and as a Bank

                                       By: /s/ David J. Campbell
                                           -------------------------
                                           Name:  David J. Campbell
                                           Title: Vice President


                                       19

<PAGE>


                                       SOUTHTRUST BANK, NATIONAL ASSOCIATION, as
                                       a Bank

                                       By: /s/ Lynn W. Feuerlein
                                           --------------------------
                                           Name:  Lynn W. Feuerlein
                                           Title: Group Vice President


                                       20

<PAGE>

                                       BANK HAPOALIM B.M., as a Bank

                                       By: /s/ Laura Anne Raffa
                                           ------------------------------
                                           Name:  Laura Anne Raffa
                                           Title: First Vice President &
                                                   Corporate Manager

                                       By: /s/ Shaun Breidbart
                                           ------------------------------
                                           Name:  Shaun Breidbart
                                           Title: Vice President


                                       21

<PAGE>


                                       ING (U.S.) CAPITAL LLC, as a Bank

                                       By: /s/ Thomas R. Hobbis
                                           ------------------------
                                           Name:  Thomas R. Hobbis
                                           Title: Vice President


                                       22

<PAGE>


                                       LASALLE BANK, National Association, as a
                                       Bank

                                       By: /s/ Peter Margolin
                                           -------------------------------
                                           Name: Peter Margolin
                                           Title: Assistant Vice President


                                       23

<PAGE>


                                       CRESTAR BANK, as a Bank

                                       By: /s/ Nancy Richards
                                           ---------------------
                                           Name: Nancy Richards
                                           Title: Vice President


                                       24

<PAGE>


                                       CHANG HWA COMMERCIAL BANK, LTD., NEW YORK
                                       BRANCH, as a Bank

                                       By: /s/ Wan-Tu Yeh
                                           ---------------------
                                           Name: Wan Tu-Yeh
                                           Title: Vice President & General
                                                   Manager


                                       25