QuickLinks -- Click here to rapidly navigate through this document

EXHIBIT 25.1

FORM T-1

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF ELIGIBILITY
UNDER THE TRUST INDENTURE ACT OF 1939 OF A
CORPORATION DESIGNATED TO ACT AS TRUSTEE

CHECK IF AN APPLICATION TO DETERMINE
ELIGIBILITY OF A TRUSTEE PURSUANT TO SECTION 305(b)(2) o

WELLS FARGO BANK, NATIONAL ASSOCIATION

(Exact name of trustee as specified in its charter)

Not Applicable	94-1347393
(State of incorporation if not a U.S. national bank)	I.R.S. employer identification no.)
505 Main Street, Suite 301 Fort Worth, Texas	76102
(Address of principal executive offices)	(Zip code)

Wells Fargo & Company
Law Department, Trust Section
MAC N9305-172
Sixth and Marquette, 17th Floor
Minneapolis, MN 55479
(agent for services)

MARKWEST ENERGY PARTNERS, L.P.

(Exact name of obligor as specified in its charter)

Delaware	27-0005456
(State or other jurisdiction of incorporation or organization)	(I.R.S. employer identification no.)

6.875% Series A Senior Notes due 2014
(Title of the indenture securities)

Item 1.    General Information.    Furnish the following information as to the trustee:

(a)

Name and address of each examining or supervising authority to which it is subject.

Comptroller of the Currency,
Treasury Department
Washington, D.C. 20230

Federal Deposit Insurance Corporation
Washington, D.C. 20429

Federal Reserve Bank of San Francisco
San Francisco, CA 94120

(b)

Whether it is authorized to exercise corporate trust powers.

The trustee is authorized to exercise corporate trust powers.

Item 2.    Affiliations with Obligor.    If the obligor is an affiliate of the trustee, describe each such affiliation.

        None with respect to the trustee.

No responses are included for Items 3-14 of this Form T-1 because the obligor is not in default as provided under Item 13.

Item 15.    Foreign Trustee.    Not applicable.

Item 16.    List of Exhibits.

Wells Fargo Bank incorporates by reference into this Form T-1 exhibits attached hereto.

Exhibit 1.	A copy of the Articles of Association of the trustee now in effect.*
Exhibit 2.	A copy of the Comptroller of the Currency Certificate of Corporate Existence for Wells Fargo Bank, National Association, dated November 28, 2001.*
Exhibit 3.	A copy of the authorization of the trustee to exercise corporate trust powers. A copy of the Comptroller of the Currency Certificate of Corporate Existence (with Fiduciary Powers) for Wells Fargo Bank, National Association, dated November 28, 2001.*
Exhibit 4.	Copy of By-laws of the trustee as now in effect.*
Exhibit 5.	Not applicable.
Exhibit 6.	The consents of United States institutional trustees required by Section 321(b) of the Act.
Exhibit 7.	Attached is a copy of the latest report of condition of the trustee published pursuant to law or the requirements of its supervising or examining authority.
Exhibit 8.	Not applicable.
Exhibit 9.	Not applicable.

*

Incorporated by reference to exhibit number 25 filed with registration statement number 333-87398.

SIGNATURE

        Pursuant to the requirements of the Trust Indenture Act of 1939, as amended, the trustee, Wells Fargo Bank, National Association, a national banking association organized and existing under the laws of the United States of America, has duly caused this statement of eligibility to be signed on its behalf by the undersigned, thereunto duly authorized, all in the City of Fort Worth and State of Texas on the 22nd day of February, 2005.

WELLS FARGO BANK, NATIONAL ASSOCIATION
By:	/s/  MELISSA SCOTT Melissa Scott, Vice President

Exhibit 6

January 28, 2005

Securities and Exchange Commission
Washington, D.C. 20549

Gentlemen:

        In accordance with Section 321(b) of the Trust Indenture Act of 1939, as amended, the undersigned hereby consents that reports of examination of the undersigned made by Federal, State, Territorial, or District authorities authorized to make such examination may be furnished by such authorities to the Securities and Exchange Commission upon its request thereof.

Very truly yours,
WELLS FARGO BANK, NATIONAL ASSOCIATION
By:	/s/  MELISSA SCOTT Melissa Scott, Vice President

Exhibit 7

Consolidated Report of Condition of

Wells Fargo Bank National Association
of 101 North Phillips Avenue, Sioux Falls, SD 57104
And Foreign and Domestic Subsidiaries,
at the close of business December 31, 2004, filed in accordance with 12 U.S.C. §161 for National Banks.

			Dollar Amounts In Millions
ASSETS
Cash and balances due from depository institutions:
	Noninterest-bearing balances and currency and coin		$	12,653
	Interest-bearing balances			3,281
Securities:
	Held-to-maturity securities			0
	Available-for-sale securities			28,571
Federal funds sold and securities purchased under agreements to resell:
	Federal funds sold in domestic offices			2,544
	Securities purchased under agreements to resell			1,114
Loans and lease financing receivables:
	Loans and leases held for sale			33,027
	Loans and leases, net of unearned income	246,371
	LESS: Allowance for loan and lease losses	2,428
	Loans and leases, net of unearned income and allowance			243,943
Trading Assets				7,177
Premises and fixed assets (including capitalized leases)				3,386
Other real estate owned				134
Investments in unconsolidated subsidiaries and associated companies				343
Customers' liability to this bank on acceptances outstanding				137
Intangible assets
	Goodwill			8,614
	Other intangible assets			8,582
Other assets				12,750
Total assets			$	366,256

LIABILITIES
Deposits:
	In domestic offices			$	264,717
		Noninterest-bearing	78,210
		Interest-bearing	186,507
	In foreign offices, Edge and Agreement subsidiaries, and IBFs				16,987
		Noninterest-bearing	4
		Interest-bearing	16,983
Federal funds purchased and securities sold under agreements to repurchase:
	Federal funds purchased in domestic offices				10,533
	Securities sold under agreements to repurchase				3,258
Trading liabilities					4,727
Other borrowed money (includes mortgage indebtedness and obligations under capitalized leases)					14,870
Bank's liability on acceptances executed and outstanding					137
Subordinated notes and debentures					5,119
Other liabilities					11,158
Total liabilities				$	331,506
Minority interest in consolidated subsidiaries					55
EQUITY CAPITAL
Perpetual preferred stock and related surplus					0
Common stock					520
Surplus (exclude all surplus related to preferred stock)					24,521
Retained earnings					8,976
Accumulated other comprehensive income					678
Other equity capital components					0
Total equity capital					34,695
Total liabilities, minority interest, and equity capital				$	366,256

I, Karen B. Martin, Vice President of the above-named bank do hereby declare that this Report of Condition has been prepared in conformance with the instructions issued by the appropriate Federal regulatory authority and is true to the best of my knowledge and belief.

        Karen B. Martin
Vice President

We, the undersigned directors, attest to the correctness of this Report of Condition and declare that it has been examined by us and to the best of our knowledge and belief has been prepared in conformance with the instructions issued by the appropriate Federal regulatory authority and is true and correct.

John Stumpf
Carrie Tolstedt
Pat Callahan Directors

QuickLinks

EXHIBIT 25.1

SIGNATURE
Exhibit 6
Exhibit 7
Consolidated Report of Condition of Wells Fargo Bank National Association of 101 North Phillips Avenue, Sioux Falls, SD 57104 And Foreign and Domestic Subsidiaries, at the close of business December 31, 2004, filed in accordance with 12 U.S.C. §161 for National Banks.