Document And Entity Information Statement - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Oct. 31, 2019	Mar. 31, 2019
Document Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Sep. 30, 2019
Document Fiscal Period Focus	Q4
Document Fiscal Year Focus	2019
Entity Registrant Name	EVOQUA WATER TECHNOLOGIES CORP.
Entity Central Index Key	0001604643
Current Fiscal Year End Date	--09-30
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Reporting Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		114,400,103
Entity Public Float			$ 665
Voluntary Filers	No
Well-known Seasoned Issuer	Yes
Current Reporting Status	Yes