diff --git a/src/nix-build/nix-build.cc b/src/nix-build/nix-build.cc
index 73d93480e..75576ef8a 100755
--- a/src/nix-build/nix-build.cc
+++ b/src/nix-build/nix-build.cc
@@ -105,7 +105,8 @@ static void main_nix_build(int argc, char * * argv)
 
     // List of environment variables kept for --pure
     std::set<string> keepVars{
-        "HOME", "USER", "LOGNAME", "DISPLAY", "PATH", "TERM", "IN_NIX_SHELL",
+        "HOME", "XDG_RUNTIME_DIR", "USER", "LOGNAME", "DISPLAY",
+        "WAYLAND_DISPLAY", "WAYLAND_SOCKET", "PATH", "TERM", "IN_NIX_SHELL",
         "NIX_SHELL_PRESERVE_PROMPT", "TZ", "PAGER", "NIX_BUILD_SHELL", "SHLVL",
         "http_proxy", "https_proxy", "ftp_proxy", "all_proxy", "no_proxy"
     };