EXHIBIT 23 Consent of Independent Accountants We hereby consent to the incorporation by reference in the Registration Statements on Form S-8 (No. 333-20829 and No. 333-20833) of MarkWest Hydrocarbon, Inc. of our report dated February 10, 1998 appearing on page 18 of this Form 10-K. PRICE WATERHOUSE LLP Denver, Colorado March 25, 1998