Figure shows that the EPA (2008; 2010) well costs scale linearly with depth, which is not consistent with our well cost analysis. This discrepancy questions the robustness of the EPA well costs because a 22 cm monitoring well should cost very similar to a 22 cm water well. The linear scaling and costs of the EPA estimates match closely with the slopes of the GeoVision "Ideal" well cost data (Section S3.3.2). The GeoVision "Ideal" well costs differ the GeoVision "Baseline" costs because the "Ideal" costs only consider a single "mono-bore" casing in the well. The monobore casing represents a new technology step that has not yet been achieved. Current well drilling practice minimizes the number of well casings to stabilize the borehole, but still requires several, depending on depth (Lowry et al., 2017). Thus, similar to the idealized GeoVision assumptions, we do not use the EPA monitoring and injection well cost estimates in genGEO.