Cover Page Document	12 Months Ended
	Sep. 30, 2020
Cover Page [Abstract]
Document Type	10-K
Documents Incorporated by Reference [Text Block]	Applicable portions of the Proxy Statement for the upcoming 2021 Annual Meeting of Stockholders of the Company are incorporated by reference into Part III of this Form 10-K.
Title of 12(b) Security	Common Stock, par value $0.01
Entity Address, Address Line Two	Suite 1200
Entity Incorporation, State or Country Code	DE
Document Transition Report	false
Document Annual Report	true
Document Period End Date	Sep. 30, 2020
Entity File Number	001-32892
Entity Registrant Name	MUELLER WATER PRODUCTS, INC.
Entity Tax Identification Number	20-3547095
Entity Address, Address Line One	1200 Abernathy Road N.E.
Entity Address, City or Town	Atlanta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30328
City Area Code	(770)
Local Phone Number	206-4200
Trading Symbol	MWA
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false