UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): February 9, 2021

EVOQUA WATER TECHNOLOGIES CORP.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (724) 772-0044

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

Item 8.01. Other Events.

On February 9, 2021, Evoqua Water Technologies Corp. (the “Company”) issued a press release announcing the pricing of a secondary public offering of 16,382,793 shares of its common stock by certain institutional shareholders of the Company, including certain affiliates of AEA Investors LP (collectively, the “Selling Shareholders”), which is expected to result in gross proceeds of approximately $407.1 million. The offering is expected to close on February 11, 2021, subject to the satisfaction of customary closing conditions.

The Company is not selling any shares in the offering and will not receive any proceeds from the sale of shares being sold by the Selling Shareholders in the offering.

It is anticipated that, upon completion of the Offering, the Selling Shareholders will have disposed of all of their remaining shares of the Company’s common stock.

A copy of the press release is attached as Exhibit 99.1 to this report and incorporated herein by reference.

The information in this Form 8-K pursuant to Item 8.01 is not an offer or the solicitation of an offer to buy securities.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits:

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.