diff --git a/app/models/case_log.rb b/app/models/case_log.rb
index 2c818c736..1446c967c 100644
--- a/app/models/case_log.rb
+++ b/app/models/case_log.rb
@@ -55,6 +55,15 @@ class CaseLogValidator < ActiveModel::Validator
     end
   end
 
+  def validate_outstanding_rent_amount(record)
+    if record.outstanding_rent_or_charges == "Yes" && record.outstanding_amount.blank?
+      record.errors.add :outstanding_amount, "You must answer the oustanding amout question if you have outstanding rent or charges."
+    end
+    if record.outstanding_rent_or_charges == "No" && record.outstanding_amount.present?
+      record.errors.add :outstanding_amount, "You must not answer the oustanding amout question if you don't have outstanding rent or charges."
+    end
+  end
+      
   EMPLOYED_STATUSES = ["Full-time - 30 hours or more", "Part-time - Less than 30 hours"].freeze
   def validate_net_income_uc_proportion(record)
     (1..8).any? do |n|
diff --git a/docs/api/DLUHC-CORE-Data.v1.json b/docs/api/DLUHC-CORE-Data.v1.json
index 1bb1fc7b1..e95b730ca 100644
--- a/docs/api/DLUHC-CORE-Data.v1.json
+++ b/docs/api/DLUHC-CORE-Data.v1.json
@@ -1207,6 +1207,17 @@
         ]
       }
     },
-    "securitySchemes": {}
+    "securitySchemes": {
+      "API Key - 1": {
+        "name": "API Key",
+        "type": "apiKey",
+        "in": "query"
+      },
+      "API Key - 2": {
+        "name": "API Key",
+        "type": "apiKey",
+        "in": "query"
+      }
+    }
   }
-}
+}
\ No newline at end of file
diff --git a/spec/models/case_log_spec.rb b/spec/models/case_log_spec.rb
index e0d03ed53..0b8d7fa1f 100644
--- a/spec/models/case_log_spec.rb
+++ b/spec/models/case_log_spec.rb
@@ -96,6 +96,23 @@ RSpec.describe Form, type: :model do
         }.to raise_error(ActiveRecord::RecordInvalid)
       end
     end
+
+    context "outstanding rent or charges validation" do
+      it "must be anwered if answered yes to outstanding rent or charges" do
+        expect {
+          CaseLog.create!(outstanding_rent_or_charges: "Yes",
+                          outstanding_amount: nil)
+        }.to raise_error(ActiveRecord::RecordInvalid)
+      end
+
+      it "must be not be anwered if answered no to outstanding rent or charges" do
+        expect {
+          CaseLog.create!(outstanding_rent_or_charges: "No",
+                          outstanding_amount: 99)
+        }.to raise_error(ActiveRecord::RecordInvalid)
+      end
+    end
+
     context "tenant’s income is from Universal Credit, state pensions or benefits" do
       it "Cannot be All if person 1 works full time" do
         expect {