Exhibit 10.1

LIMITED WAIVER AGREEMENT

     THIS LIMITED WAIVER AGREEMENT, hereinafter referred to as this “Waiver”, dated as of June 30, 2011, is made and entered into by and among Duncan Energy Partners L.P., a Delaware limited partnership (the “Borrower”), the Lenders party hereto and Wells Fargo Bank, National Association, successor-in-interest to Wachovia Bank, National Association, as Administrative Agent under that certain Term Loan Agreement (as amended, the “Term Loan Agreement”) dated as of April 18, 2008, among the Borrower, Wells Fargo Bank, National Association, as Administrative Agent, and the Lenders party thereto.

     WHEREAS, the Borrower projects its Leverage Ratio to slightly exceed 5.00 to 1.00 in the second and third fiscal quarters of 2011 and has requested the Administrative Agent and Lenders waive the covenant set forth in Section 6.07(b) of the Term Loan Agreement with respect thereto for fiscal quarters ending June 30, 2011 and September 30, 2011, and the Administrative Agent and the Lenders party hereto are willing to do so.

     NOW, THEREFORE, subject to the conditions and limitations set forth herein, and in consideration of the premises and the mutual agreements herein set forth, and for other good and valuable consideration, the Borrower, the Administrative Agent and the Lenders party hereto do hereby agree as follows:

The requirement of Section 6.07(b) of the Term Loan Agreement is hereby waived for fiscal quarters ending June 30, 2011 and September 30, 2011. PROVIDED, for purposes of subsection (a) of the definition of “Applicable Rate” set forth in Section 1.01 of the Term Loan Agreement, commencing July 1, 2011, the Leverage Ratio shall be deemed to be greater than 5.00 to 1.00 until but not including the first Business Day immediately following the date a compliance certificate is delivered pursuant to Section 5.01(d) certifying that the Leverage Ratio is less than or equal to 5.00 to 1.00

     Borrower hereby represents and warrants to Administrative Agent and Lenders that there exists no Default or Event of Default after giving effect to the waiver set forth herein, and all representations and warranties contained herein, in the Term Loan Agreement or otherwise made in writing by Borrower in connection herewith or therewith were true and correct in all material respects when made, and are true and correct in all material respects at and as of the date hereof, except, in each case, to the extent such representations and warranties relate to an earlier date, in which case such representations and warranties were true and correct in all material respects as of such earlier date.

     Except as expressly waived or agreed herein, all covenants, obligations and agreements of Borrower contained in the Term Loan Agreement shall remain in full force and effect in accordance with their terms. Without limitation of the foregoing, the consents and agreements set forth herein are limited precisely to the extent set forth herein and shall not be deemed to (a) be a consent or agreement to, or waiver or modification of, any other term or condition of the Term Loan Agreement or any of the documents referred to therein, or (b) except as expressly set forth herein, prejudice any right or rights which Administrative Agent or any Lender may now have or may have in the future under or in connection with the Term Loan Agreement or any of the documents referred to therein. Except as expressly modified hereby, the terms and provisions of the Term Loan Agreement and any other documents or instruments executed in connection with any of the foregoing, are and hall remain in full force and effect in accordance with their terms, and the same are hereby ratified and confirmed by Borrower in all respects.

     Borrower agrees to reimburse and save Administrative Agent harmless from and against liabilities for the payment of all out-of-pocket costs and expenses arising in connection with the preparation, execution, delivery, amendment, modification, waiver and enforcement of, or the preservation of any rights under, this Limited Waiver, including, without limitation, the reasonable fees and expenses of legal counsel to Administrative Agent which may be payable in respect of, or in respect of any modification of, this Limited Waiver.

     This Limited Waiver, and the rights and obligations of the parties hereunder, shall be construed in accordance with and be governed by the laws of the State of New York.

     This Limited Waiver, and the documents referred to herein, represent the entire understanding of the parties hereto regarding the subject matter hereof and supersede all prior and contemporaneous oral and written agreements of the parties hereto with respect to the subject matter hereof.

     This Limited Waiver may be separately executed in counterparts and by the different parties hereto in separate counterparts, each of which when so executed shall be deemed to constitute one and the same agreement.

     IN WITNESS WHEREOF, the parties hereto have caused this Waiver to be signed by their respective duly authorized officers, effective as of the date first set forth herein.

Bank of Nova Scotia

Name of Lender

The Bank of Tokyo — Mitsubishi UFJ, Ltd.

Name of Lender

Barclays Bank PLC

Name of Lender

Citibank, N. A.

Name of Lender

DnB NOR Bank ASA

Name of Lender

JPMorgan Chase Bank, N. A.

Name of Lender

Mizuho Corporate Bank, Ltd.

Name of Lender

Morgan Stanley Bank, N. A

Name of Lender

The Royal Bank of Scotland plc

Name of Lender

UBS AG, Stamford Branch

Name of Lender