Description of the Company and Basis of Presentation	3 Months Ended
Description of the Company and Basis of Presentation	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of the Company and Basis of Presentation	Description of the Company and Basis of Presentation Background Evoqua Water Technologies Corp. (referred to herein as the “Company” or “EWT”) is a holding company and does not conduct any business operations of its own. The Company was incorporated on October 7, 2013. On January 15, 2014, the Company acquired through its wholly owned entities, EWT Holdings II Corp. and EWT Holdings III Corp. (“EWT III”), all of the outstanding shares of Siemens Water Technologies, a group of legal entity businesses formerly owned by Siemens AG (“Siemens”). The stock purchase closed on January 15, 2014 and was effective January 16, 2014 (the “Acquisition”). On November 6, 2017, the Company completed its initial public offering (“IPO”). On December 4, 2020, the Company completed a secondary public offering, pursuant to which 12,000 shares of common stock were sold by certain selling shareholders. The Company did not receive any proceeds from the sale of shares by the selling shareholders in this secondary public offering. The Business EWT provides a wide range of product brands and advanced water and wastewater treatment systems and technologies, as well as mobile and emergency water supply solutions and service contract options through its branch network. Headquartered in Pittsburgh, Pennsylvania, EWT is a multinational corporation with operations in the United States (“U.S.”), Canada, the United Kingdom (“UK”), the Netherlands, Germany, Australia, the People’s Republic of China, Singapore, the Republic of Korea and India. The Company is organizationally structured into two reportable operating segments for the purpose of making operational decisions and assessing financial performance: (i) Integrated Solutions and Services and (ii) Applied Product Technologies. Basis of Presentation The accompanying Unaudited Consolidated Financial Statements have been prepared in accordance with accounting principles generally accepted in the U.S. (“GAAP”). All intercompany transactions have been eliminated. Unless otherwise specified, all dollar and share amounts in these notes are referred to in thousands. The interim Unaudited Consolidated Financial Statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such SEC rules. We believe that the disclosures made are adequate to make the information presented not misleading. In our opinion, all adjustments considered necessary for a fair presentation of the financial statements have been included, and all adjustments are of a normal and recurring nature. We consistently applied the accounting policies described in our Annual Report on Form 10-K for the fiscal year ended September 30, 2020, as filed with the SEC on November 20, 2020 (“2020 Annual Report”), in preparing these Unaudited Consolidated Financial Statements, with the exception of accounting standard updates described in Note 2, “Recent Accounting Pronouncements.” These Unaudited Consolidated Financial Statements should be read in conjunction with the audited financial statements and the notes included in our 2020 Annual Report. Certain prior period amounts have been reclassified to conform to the current period presentation.