Exhibit J

JOINT FILING AGREEMENT

We, the undersigned, hereby express our agreement that the attached Schedule 13D with respect to the beneficial ownership by the undersigned of the common units of Crestwood Midstream Partners LP is, and any further amendments thereto signed by each of the undersigned shall be, filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934. This agreement may be terminated with respect to the obligations to jointly file future amendments to such statement on Schedule 13D as to any of the undersigned upon such person giving written notice thereof to each of the other persons signatory hereto, at the principal office thereof.

Dated: May 6, 2015

CRESTWOOD GAS SERVICES HOLDINGS LLC
By:	/s/ Joel C. Lambert
	Name:	Joel C. Lambert
	Title:	Senior Vice President
CRESTWOOD HOLDINGS LLC
By:	/s/ Joel C. Lambert
	Name:	Joel C. Lambert
	Title:	Senior Vice President
CRESTWOOD HOLDINGS II LLC
By:	/s/ Joel C. Lambert
	Name:	Joel C. Lambert
	Title:	Senior Vice President
CRESTWOOD HOLDINGS PARTNERS, LLC
By:	/s/ Joel C. Lambert
	Name:	Joel C. Lambert
	Title:	Senior Vice President
CRESTWOOD GAS SERVICES GP, LLC
By:	/s/ Joel C. Lambert
	Name:	Joel C. Lambert
	Title:	Senior Vice President

CRESTWOOD MIDSTREAM GP LLC
By:	/s/ Joel C. Lambert
	Name:	Joel C. Lambert
	Title:	Senior Vice President
CRESTWOOD MIDSTREAM HOLDINGS LP
By: MGP GP LLC, its general partner
By:	/s/ Joel C. Lambert
	Name:	Joel C. Lambert
	Title:	Senior Vice President
MGP GP LLC
By:	/s/ Joel C. Lambert
	Name:	Joel C. Lambert
	Title:	Senior Vice President
CRESTWOOD EQUITY PARTNERS LP
By:	Crestwood Equity GP LLC, its general partner
By:	/s/ Joel C. Lambert
	Name:	Joel C. Lambert
	Title:	Senior Vice President
CRESTWOOD EQUITY GP LLC
By:	/s/ Joel C. Lambert
	Name:	Joel C. Lambert
	Title:	Senior Vice President
CRESTWOOD HOLDINGS LP
By:	Crestwood Holdings LLC, its general partner
By:	/s/ Joel C. Lambert
	Name:	Joel C. Lambert
	Title:	Senior Vice President

FR XI CMP HOLDINGS LLC
By:	First Reserve GP XI, L.P., its managing member
By:	First Reserve GP XI, Inc., its general partner
By:	/s/ Michael France
	Name:	Michael France
	Title:	Managing Director
FR MIDSTREAM HOLDINGS LLC
By:	First Reserve GP XI, L.P., its managing member
By:	First Reserve GP XI, Inc., its general partner
By:	/s/ Michael France
	Name:	Michael France
	Title:	Managing Director
FIRST RESERVE GP XI, L.P.
By:	First Reserve GP XI, Inc., its general partner
By:	/s/ Michael France
	Name:	Michael France
	Title:	Managing Director
FIRST RESERVE GP XI, INC.
By:	/s/ Michael France
	Name:	Michael France
	Title:	Managing Director
WILLIAM E. MACAULAY
By:	/s/ Anne E. Gold
	Name:	Anne E. Gold
	Title:	Attorney-in-fact