diff --git a/nixos/modules/installer/tools/nixos-rebuild.sh b/nixos/modules/installer/tools/nixos-rebuild.sh
index 08813d17ff9..e452e24d263 100644
--- a/nixos/modules/installer/tools/nixos-rebuild.sh
+++ b/nixos/modules/installer/tools/nixos-rebuild.sh
@@ -68,7 +68,7 @@ while [ "$#" -gt 0 ]; do
         j="$1"; shift 1
         extraBuildFlags+=("$i" "$j")
         ;;
-      --show-trace|--keep-failed|-K|--keep-going|-k|--verbose|-v|-vv|-vvv|-vvvv|-vvvvv|--fallback|--repair|--no-build-output|-Q|-j*|-L|--refresh|--no-net)
+      --show-trace|--keep-failed|-K|--keep-going|-k|--verbose|-v|-vv|-vvv|-vvvv|-vvvvv|--fallback|--repair|--no-build-output|-Q|-j*|-L|--refresh|--no-net|--impure)
         extraBuildFlags+=("$i")
         ;;
       --option)