diff --git a/python/nav/config.py b/python/nav/config.py
index 340195aef2..6c0c4d2c84 100644
--- a/python/nav/config.py
+++ b/python/nav/config.py
@@ -42,7 +42,7 @@
     '/etc/nav',
     os.path.join(buildconf.datadir, 'conf'),
 ]
-_venv = os.getenv('VIRTUAL_ENV')
+_venv = sys.prefix if sys.prefix != sys.base_prefix else None
 if _venv:
     CONFIG_LOCATIONS = [
         os.path.join(_venv, 'etc'),