Exhibit 4.1


SUPPLEMENTAL INDENTURE


SUPPLEMENTAL INDENTURE
(this “Supplemental Indenture”), dated as of October 3,
2005, is entered into by and among Mueller Water Products Co-Issuer, Inc.
(the “Co-Issuer”), a subsidiary of Mueller
Water Products, LLC (the “Company”), the
Company and Law Debenture Trust Company of New York, as trustee under the
Indenture referred to below (the “Trustee”).


W I T N E
S S E T H


WHEREAS, the Company has heretofore executed and
delivered to the Trustee an indenture (the “Indenture”),
dated as of April 29, 2004, providing for the issuance of 143⁄4% Senior
Discount Notes due 2014 (the “Notes”);


WHEREAS, the Company has converted to a limited
liability company, and the Indenture provides that under certain circumstances
the Co-Issuer shall execute and deliver to the Trustee a supplemental indenture
pursuant to which the Co-Issuer shall become a co-issuer of the Notes;


WHEREAS, pursuant to Section 9.01 of the
Indenture, the Trustee is authorized to execute and deliver this Supplemental Indenture.


NOW, THEREFORE, in consideration of the foregoing and
for other good and valuable consideration, the receipt of which is hereby
acknowledged, the Co-Issuer and the Trustee mutually covenant and agree for the
equal and ratable benefits of the Holders of the Notes as follows:


1.     Capitalized Terms.   Capitalized
terms used herein without definition shall have the meanings assigned to them
in the Indenture.


2.     Agreement to Co-Issue.   The
Co-Issuer hereby agrees to be deemed the co-issuer of the Notes under the terms
and subject to the conditions set forth in the Indenture, and shall, jointly
with the Company, assume all obligations of the Company under the Notes, the
Indenture and the Registration Rights Agreement.


3.     No Recourse Against
Others.   No past, present or future director, officer, employee,
incorporator, stockholder or agent of the Co-Issuer, as such, shall have any
liability for any obligations of the Company or the Co-Issuer under the Notes,
the Indenture or this Supplemental Indenture or for any claim based on, in
respect of, or by any reason of, such obligations or their creation. Each
Holder of the Notes by accepting a Note waives and releases all such liability.
The waiver and release are part of the consideration for issuance of the Notes.


4.     NEW YORK LAW TO GOVERN.   THE INTERNAL LAW OF THE STATE OF
NEW YORK SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE
WITHOUT GIVING EFFECT TO THE APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE
EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE
REQUIRED THEREBY.


5.     Counterparts.   The
parties may sign any number of copies of this Supplemental Indenture. Each
signed copy shall be an original, but all of them together represent the same
agreement.











IN WITNESS WHEREOF, the
parties hereto have caused this Supplemental Indenture to be duly executed and
attested, all as of the date above first written.




	
   

  	
  MUELLER
  WATER PRODUCTS, LLC.

  
	
   

  	
  By:

  	
  /s/ MILES C.
  DEARDEN, III

  
	
   

  	
   

  	
  Name:

  	
  Miles C. Dearden, III

  
	
   

  	
   

  	
  Title:

  	
  Vice President

  
	
   

  	
  MUELLER WATER PRODUCTS
  CO-ISSUER, INC.

  
	
   

  	
  By:

  	
  /s/ JOSEPH J.
  TROY

  
	
   

  	
   

  	
  Name:

  	
  Joseph J. Troy

  
	
   

  	
   

  	
  Title:

  	
  President

  
	
   

  	
  LAW DEBENTURE TRUST COMPANY
  OF NEW YORK

  
	
   

  	
  By:

  	
  /s/ PATRICK J.
  HEALY

  
	
   

  	
   

  	
  Name:

  	
  Patrick J. Healy

  
	
   

  	
   

  	
  Title:

  	
  Vice President