diff --git a/site/models/lease.php b/site/models/lease.php
index b8bcab4..ab4966f 100644
--- a/site/models/lease.php
+++ b/site/models/lease.php
@@ -347,6 +347,8 @@ class Lease extends AppModel {
     $this->pr(17, compact('date', 'charge_through_date')
 	      + array('date_str' => date('Y-m-d', $date),
 		      'charge_through_date_str' => date('Y-m-d', $charge_through_date)));
+    if (!$charge_through_date)
+      return $this->prReturn(null);
     if ($charge_through_date >= $date)
       return $this->prReturn(null);