Unaudited Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenues [Abstract]
Revenues	$ 439,325	$ 369,681	$ 1,232,321	$ 1,038,438
Cost of Revenue [Abstract]
Cost of product sales and services	(303,193)	(252,652)	(856,795)	(720,145)
Gross profit	136,132	117,029	375,526	318,293
Operating Expenses [Abstract]
General and administrative expense	(61,426)	(50,837)	(186,231)	(146,048)
Sales and marketing expense	(40,634)	(35,871)	(116,942)	(103,629)
Research and development expense	(3,857)	(3,413)	(11,060)	(9,929)
Total operating expenses	(105,917)	(90,121)	(314,233)	(259,606)
Other operating income	951	1,662	4,023	2,653
Other operating expense	(136)	(260)	(426)	(618)
Operating profit (loss)	31,030	28,310	64,890	60,722
Interest expense	(8,440)	(11,224)	(24,969)	(28,292)
Income before income taxes	22,590	17,086	39,921	32,430
Income tax expense	(5,027)	(3,887)	(8,896)	(7,672)
Net income	17,563	13,199	31,025	24,758
Net income attributable to non‑controlling interest	0	44
Net income attributable to Evoqua Water Technologies Corp.	$ 17,563	$ 13,155	$ 30,880	$ 24,624
Basic income per common share	$ 0.14	$ 0.11	$ 0.26	$ 0.21
Diluted income per common share	$ 0.14	$ 0.11	$ 0.25	$ 0.20
Non-controlling Interest
Operating Expenses [Abstract]
Net income	$ 0	$ 44
Net income attributable to non‑controlling interest			$ 145	$ 134
Revenue from product sales
Revenues [Abstract]
Revenues	267,957	218,427	740,300	600,908
Cost of Revenue [Abstract]
Cost of product sales and services	(185,742)	(152,591)	(524,867)	(428,173)
Revenue from service
Revenues [Abstract]
Revenues	171,368	151,254	492,021	437,530
Cost of Revenue [Abstract]
Cost of product sales and services	$ (117,451)	$ (100,061)	$ (331,928)	$ (291,972)