Page 1

energy recovery " Energy Recovery Sets Product Revenue Record in the First Quarter SAN LEANDRO , Calif . - May 6 , 2021 - Energy Recovery , Inc. ( Nasdaq : ERII ) today announced its financial results for the first quarter ended March 31 , 2021. The Company posted record - high quarterly product revenue in its core Water segment with 52 % growth compared to the first quarter of 2020 . " Today , Energy Recovery is at a key inflection point as we embark on a path of sustainable , disciplined , and diversified growth . First , we must protect and grow our seawater desalination business , which is thriving as our quarterly results show , " said Robert Mao , Chairman of the Board , President , and Chief Executive Officer of Energy Recovery . Mr. Mao continued , " Second , we are expanding our pressure exchanger technology's aperture and developing pressure exchanger - based solutions for new industries . We specifically look for markets where we can reduce costs and accelerate customers ' environmental sustainability . I am particularly excited by our progress developing an energy recovery device for carbon dioxide ( CO₂ ) commercial refrigeration . The U.S. Environmental Protection Agency just this week announced an accelerated phase out of HFCs which should hasten adoption of CO₂ technology in the U.S. in the coming years . Our testing indicates that our solution excels at saving energy where today's market - leading technology fails – in warmer climates . " Mr. Mao concluded , " The coming months will be an exciting time for Energy Recovery . Significant growth in our core desalination market , combined with our strong financial position and exciting research and development ( " R & D " ) results , gives us confidence that the future is bright . " Financial Results Product revenue License and development revenue Total revenue Product gross profit Product gross margin Operating expense Operating income Net income Diluted net income per share Operating cash flow Cash and investments Product Channel Revenue Megaproject Original equipment manufacturer Aftermarket Total product revenue $ $ $ $ A A $ $ A A $ A A $ $ 2021 Variance Three Months Ended March 31 , 2020 ( In millions , except net income per share , percentages and basis points ) 28.9 $ 28.9 20.0 $ 69.0 % 13.8 6.1 6.9 0.12 0.1 120.0 2021 $ 23.7 2.8 2.4 28.9 $ $ LA LA $ $ Exhibit 99.1 19.0 2.5 21.5 $ 13.3 70.1 % 15.7 0.1 0.6 0.01 $ ( 5.9 ) 93.2 $ Three Months Ended March 31 , 2020 ( In millions , except percentages ) $ 14.4 3.6 1.0 19.0 52 % ( 100 % ) 34 % 50 % ( 110 ) bps ( 12 % ) 4700 % 1006 % 0.11 5.9 29 % Variance 64 % ( 22 % ) 142 % 52 %