In their recent paper in Environmental Research Letters, 'Egypt's water budget deficit and suggested mitigation policies for the Grand Ethiopian Renaissance Dam (GERD) filling scenarios,' Heggy et al (2021 Environ. Res. Lett. 16 074022) paint an alarming picture of the water deficits and economic impacts for Egypt that will occur as a consequence of the filling of the GERD. These and other numbers in the paper are inconsistent with the best scientific and economic knowledge of the Nile Basin and are not a dependable source of information for policy-makers or the general public. In this response to Heggy et al, the authors, who include the Jameel Index for Food Trade and Vulnerability project lead, Kenneth Strzepek, draw on high quality peer-reviewed literature and appropriate modelling methods to identify and analyse many flaws in their article.