QuickLinks -- Click here to rapidly navigate through this documentExhibit 23.1
CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
We consent to the incorporation by reference in this Amendment No. 1 to the Registration Statement No. 333-160420 on Form S-4 of our report dated March 2, 2009 (May 18, 2009 as to the effects of the adoption of SFAS 160 and FSP EITF 03-6-1 and the related disclosures in Notes 1, 2 and 21), relating to the consolidated financial statements of MarkWest Energy Partners, L.P. and subsidiaries (which report expressed an unqualified opinion and included an explanatory paragraph concerning the retrospective adjustments related to the adoption of SFAS 160 and FSP EITF 03-6-1), appearing in the current report on Form 8-K of MarkWest Energy Partners, L.P. dated May 18, 2009, and our report dated March 2, 2009 relating to the effectiveness of MarkWest Energy Partners L.P. and subsidiaries' internal control over financial reporting, appearing in the Annual Report on Form 10-K of MarkWest Energy Partners, L.P. for the year ended December 31, 2008, and to the reference to us under the heading "Experts" in the Prospectus, which is part of this Registration Statement.
/s/ DELOITTE & TOUCHE LLP
Denver, Colorado
October 16, 2009
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CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
