diff --git a/src/cat.sol b/src/cat.sol
index 5a2fa2e7..32f168d8 100644
--- a/src/cat.sol
+++ b/src/cat.sol
@@ -42,7 +42,7 @@ interface VatLike {
 }
 
 interface VowLike {
-    function fess(uint256) external;
+    function fess(uint256,uint256) external;
 }
 
 contract Cat is LibNote {
@@ -60,6 +60,7 @@ contract Cat is LibNote {
         address flip;  // Liquidator
         uint256 chop;  // Liquidation Penalty  [wad]
         uint256 dunk;  // Liquidation Quantity [rad]
+        uint256 wait;  // Bad debt grace period [seconds]
     }
 
     mapping (bytes32 => Ilk) public ilks;
@@ -116,6 +117,7 @@ contract Cat is LibNote {
     function file(bytes32 ilk, bytes32 what, uint256 data) external note auth {
         if (what == "chop") ilks[ilk].chop = data;
         else if (what == "dunk") ilks[ilk].dunk = data;
+        else if (what == "wait") ilks[ilk].wait = data;
         else revert("Cat/file-unrecognized-param");
     }
     function file(bytes32 ilk, bytes32 what, address flip) external note auth {
@@ -155,7 +157,7 @@ contract Cat is LibNote {
         vat.grab(
             ilk, urn, address(this), address(vow), -int256(dink), -int256(dart)
         );
-        vow.fess(mul(dart, rate));
+        vow.fess(add(now, milk.wait), mul(dart, rate));
 
         { // Avoid stack too deep
             // This calcuation will overflow if dart*rate exceeds ~10^14,
diff --git a/src/vow.sol b/src/vow.sol
index 2585c80e..1c635cbc 100644
--- a/src/vow.sol
+++ b/src/vow.sol
@@ -54,11 +54,10 @@ contract Vow is LibNote {
     FlapLike public flapper;   // Surplus Auction House
     FlopLike public flopper;   // Debt Auction House
 
-    mapping (uint256 => uint256) public sin;  // debt queue
+    mapping (uint256 => uint256) public sin; // debt queue
     uint256 public Sin;   // Queued debt            [rad]
     uint256 public Ash;   // On-auction debt        [rad]
 
-    uint256 public wait;  // Flop delay             [seconds]
     uint256 public dump;  // Flop initial lot size  [wad]
     uint256 public sump;  // Flop fixed bid size    [rad]
 
@@ -109,13 +108,13 @@ contract Vow is LibNote {
     }
 
     // Push to debt-queue
-    function fess(uint tab) external note auth {
-        sin[now] = add(sin[now], tab);
+    function fess(uint era, uint tab) external note auth {
+        sin[era] = add(sin[era], tab);
         Sin = add(Sin, tab);
     }
     // Pop from debt-queue
     function flog(uint era) external note {
-        require(add(era, wait) <= now, "Vow/wait-not-finished");
+        require(era <= now, "Vow/wait-not-finished");
         Sin = sub(Sin, sin[era]);
         sin[era] = 0;
     }