diff --git a/common/global/nix.nix b/common/global/nix.nix
index 8abef08..4a52908 100644
--- a/common/global/nix.nix
+++ b/common/global/nix.nix
@@ -1,3 +1,8 @@
 {
   nix.settings.trusted-users = [ "root" "@wheel" ];
+  nix.gc = {
+    automatic = true;
+    dates = "weekly";
+    options = "--delete-older-than 30d";
+  };
 }