X0306 4 2019-07-16 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 2019-07-16 4 M 0 5000 2.14 A 53432 D Common Stock 2019-07-16 4 S 0 5000 12 D 48432 D Common Stock 2019-07-18 4 F 0 229 10.19890 D 48203 D Employee Stock Option (Right to Buy) 2.14 2019-07-16 4 M 0 5000 0 D 2025-09-30 Common Stock 5000 35000 D This transaction was effected pursuant to a 10b5-1 trading plan adopted by the Reporting Person on December 14, 2018. Payment of tax obligation by withholding securities incident to the vesting of the securities in accordance with Rule 16b-3(e). Represents the weighted average stock price of the shares withheld to cover the tax obligation for each restricted stock unit award vesting. This employee stock option was granted on 09/30/2015. 25% of the shares full vest on the 1st anniversary of the vesting start date; thereafter, the remaining 75% vesting 1/36th per month. /s/ William Yeung, Attorney-in-Fact for Emily Smith 2019-07-18