FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Expires: December 31, 2014 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person * Yeung William (Last) (First) (Middle) C/O ENERGY RECOVERY, INC. 1717 DOOLITTLE DRIVE (Street) SAN LEANDRO CA 94577 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Energy Recovery, Inc. [ ERII ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director 10% Owner X Officer (give title below) Other (specify below) General Counsel
	3. Date of Earliest Transaction (Month/Day/Year) 03/21/2018
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock (1) (2)	03/21/2018		A		11,572	A	$ 0	41,982	D
Common Stock								8,068	I	Spouse

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Each restricted stock unit represents the right to receive, at settlement, one (1) share of common stock.

2. This restricted stock unit award was granted March 21, 2018 and vests 100% on September 21, 2019.

	/s/ Derek Ching, Attorney-in-Fact for William Young	03/23/2018
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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Exhibit 24

POWER OF ATTORNEY

As an officer and/or director of Energy Recovery, Inc. (the "Company"), the undersigned is subject to the reporting requirements of Section 16 of the Securities Exchange Act of 1934, as amended.

By signing this document, the undersigned: (i) expressly revokes and leaves without effect any and all prior powers of attorney granted as an officer and/or a director of the Company for the purposes set-forth in points 1 to 3 herein below; and (ii) designates and appoints each of Joel Gay, Chris Gannon and Derek Ching as the undersigned's true and lawful attorney-in-fact to:

(1) prepare and execute Forms ID, 3, 4, and 5 including amendments to these Forms, for and on behalf the undersigned, in the undersigned's capacity as an officer and/or director of the Company;

(2) prepare and execute any other forms or amendments to such forms as he or she determines, in his or her discretion, that are required or advisable to be filed under Section 16, as amended, and related rules and regulations, including any successor laws and regulations, as a consequence of the undersigned's status as a director or as a result of the undersigned's ownership, acquisition or disposition of securities of the Company; and

(3) undertake all acts necessary in order to file and submit such forms to the U.S. Securities and Exchange Commission, any securities exchange or national association, the Company and such other person or agency as the attorney-in-fact deems appropriate.

The undersigned hereby grants to each such attorney-in-fact full power and authority to do and perform any and every act and thing whatsoever requisite, necessary or proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as the undersigned might or could do if personally present, with full power of substitution or revocation, hereby ratifying and confirming all that such attorney-in-fact, or such attorney-in-fact's substitute or substitutes, shall lawfully do or cause to be done by virtue of this Power of Attorney and the rights and powers herein granted.  The undersigned hereby ratifies and confirms all acts that each of the attorneys-in-fact and agents do or cause to be done by virtue of this Power of Attorney.  The undersigned acknowledges that each of the attorneys-in-fact, in serving in such capacity at the undersigned's request, are not assuming, nor is the Company assuming, any of the undersigned's responsibilities to comply with Section 16, as amended.

This Power of Attorney shall remain in full force and effect until the undersigned is no longer required to file Forms ID, 3, 4, and 5 or to report holdings of, and transactions in, securities issued by the Company, or until the undersigned revokes this Power of Attorney by delivering to the Company a signed revocation in writing to the Company and to each of the attorneys-in-fact.

IN WITNESS WHEREOF, I have caused this Power of Attorney to be executed as of this 1st day of December, 2017.


/s/William Yeung
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William Yeung

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