diff --git a/flopy/seawat/swt.py b/flopy/seawat/swt.py
index 410b63652..da3d87e64 100644
--- a/flopy/seawat/swt.py
+++ b/flopy/seawat/swt.py
@@ -175,6 +175,7 @@ def modelgrid(self):
                                          self.dis.top.array,
                                          self.dis.botm.array,
                                          idomain=ibound,
+                                         lenuni=self.dis.lenuni,
                                          proj4=self._modelgrid.proj4,
                                          epsg=self._modelgrid.epsg,
                                          xoff=self._modelgrid.xoffset,