X0306 4 2019-02-15 0001421517 Energy Recovery, Inc. ERII 0001668423 Smith Emily C/O ENERGY RECOVERY 1717 DOOLITTLE DRIVE SAN LEANDRO CA 94577 1 VP, Corporate Development Common Stock 2019-02-15 4 M 0 10000 2.14 A 66776 D Common Stock 2019-02-15 4 S 0 10000 8.0035 D 56776 D Common Stock 2019-02-19 4 F 0 135 7.83 D 56641 D Employee Stock Option (Right to Buy) 2.14 2019-02-15 4 M 0 10000 0 D 2025-09-30 Common Stock 10000 40000 D This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on December 14, 2018. This figure is the weighted average sales price of multiple trades ranging from $7.9300 to $8.0500 per share. The Reporting Person undertakes to provide the SEC Staff, ERI or a shareholder of ERI full information about the number of shares sold at each separate price upon request. Payment of tax obligation by withholding securities incident to the vesting of the securities in accordance with Rule 16b-3. This employee stock option was granted on September 30, 2015. 25% of the shares full vest on the 1st anniversary of the vesting start date; thereafter, the remaining 75% vest 1/36th per month. /s/ William Yeung, Attorney-in-Fact for Emily Smith 2019-02-19