diff --git a/nixos/modules/services/continuous-integration/hydra/default.nix b/nixos/modules/services/continuous-integration/hydra/default.nix
index 2fd38e50459d2..65df56ef39f15 100644
--- a/nixos/modules/services/continuous-integration/hydra/default.nix
+++ b/nixos/modules/services/continuous-integration/hydra/default.nix
@@ -360,7 +360,7 @@ in
         ${lib.optionalString haveLocalDB ''
           if ! [ -e ${baseDir}/.db-created ]; then
             runuser -u ${config.services.postgresql.superUser} ${config.services.postgresql.package}/bin/createuser hydra
-            runuser -u ${config.services.postgresql.superUser} ${config.services.postgresql.package}/bin/createdb -O hydra hydra
+            runuser -u ${config.services.postgresql.superUser} ${config.services.postgresql.package}/bin/createdb -- -O hydra hydra
             touch ${baseDir}/.db-created
           fi
           echo "create extension if not exists pg_trgm" | runuser -u ${config.services.postgresql.superUser} -- ${config.services.postgresql.package}/bin/psql hydra