FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * STROUD ANDREW B JR   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) VP, Human Resources (Last) (First) (Middle) C/O ENERGY RECOVERY, INC., 1717 DOOLITTLE DRIVE 3. Date of Earliest Transaction (Month/Day/Year) 02/01/2018 (Street) SAN LEANDRO, CA 94577 4. If Amendment, Date 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 (City) (State) (Zip) 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 02/01/2018   F   243 (1) D $ 9.56 (2) 22,842 D   Common Stock (3) 02/01/2018   A   15,000 A $ 7.5 37,842 D   Common Stock 02/05/2018   F   1,160 (4) D $ 7.7725 (5) 36,682 D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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 Underlying Securities (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 of Derivative Security: 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

Employee Stock Option (Right to Buy)

$ 7.5

02/01/2018

A

26,023

(6)

02/01/2028

Common Stock

26,023

$ 0

26,023

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
STROUD ANDREW B JR C/O ENERGY RECOVERY, INC. 1717 DOOLITTLE DRIVE SAN LEANDRO, CA 94577			VP, Human Resources

Signatures

/s/ Derek Ching, Attorney-in-Fact for Andrew B. Stroud, Jr.		02/05/2018
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	Payment of tax obligation by withholding securities incident to the vesting of securities in accordance with Rule 16b-3(e).
(2)	Represents the weighted average stock price of the shares withheld for each restricted stock unit award vesting.
(3)	This restricted stock unit award was granted February 1, 2018 and vests 25% on each of the first four anniversaries of the grant date.
(4)	Payment of tax obligation by selling securities incident to the vesting of securities in accordance with Rule 16b-3(e).
(5)	Represents the weighted average stock price of the shares sold to cover tax obligation for restricted stock unit award vesting.
(6)	This employee stock option was granted on February 1, 2018. 25% of the shares fully vest on the 1st anniversary of the vesting start date; thereafter, the remaining 75%, vest 1/36th per month.
Remarks: Exhibit 24, Power of Attorney

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