diff --git a/app/models/case_log.rb b/app/models/case_log.rb
index 86ea4e7c2..ac956fd20 100644
--- a/app/models/case_log.rb
+++ b/app/models/case_log.rb
@@ -351,6 +351,13 @@ private
       self.vmonth = property_void_date.month
       self.vyear = property_void_date.year
     end
+    if rsnvac.present?
+      self.newprop = if has_first_let_vacancy_reason?
+                       1
+                     else
+                       2
+                     end
+    end
     self.incref = 1 if net_income_refused?
     self.hhmemb = other_hhmemb + 1 if other_hhmemb.present?
     self.renttype = RENT_TYPE_MAPPING[rent_type]
diff --git a/db/migrate/20220325114252_add_newprop_derived_variable.rb b/db/migrate/20220325114252_add_newprop_derived_variable.rb
new file mode 100644
index 000000000..0e30498a0
--- /dev/null
+++ b/db/migrate/20220325114252_add_newprop_derived_variable.rb
@@ -0,0 +1,7 @@
+class AddNewpropDerivedVariable < ActiveRecord::Migration[7.0]
+  def change
+    change_table :case_logs, bulk: true do |t|
+      t.column :newprop, :integer
+    end
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 545cecd7d..30a624de6 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -230,6 +230,7 @@ ActiveRecord::Schema[7.0].define(version: 202202071123100) do
     t.string "relat6"
     t.string "relat7"
     t.string "relat8"
+    t.integer "newprop"
     t.index ["managing_organisation_id"], name: "index_case_logs_on_managing_organisation_id"
     t.index ["owning_organisation_id"], name: "index_case_logs_on_owning_organisation_id"
   end
diff --git a/spec/fixtures/exports/case_logs.xml b/spec/fixtures/exports/case_logs.xml
index 639768427..c6e79746a 100644
--- a/spec/fixtures/exports/case_logs.xml
+++ b/spec/fixtures/exports/case_logs.xml
@@ -172,5 +172,6 @@
     <relat6/>
     <relat7/>
     <relat8/>
+    <newprop>2</newprop>
   </form>
 </forms>
diff --git a/spec/models/case_log_spec.rb b/spec/models/case_log_spec.rb
index 3b506e02e..b768f12dd 100644
--- a/spec/models/case_log_spec.rb
+++ b/spec/models/case_log_spec.rb
@@ -1577,6 +1577,38 @@ RSpec.describe CaseLog do
         end
       end
     end
+
+    context "when the data provider is filling in the reason for the property being vacant" do
+      let!(:first_let_case_log) do
+        described_class.create({
+          managing_organisation: organisation,
+          owning_organisation: organisation,
+          first_time_property_let_as_social_housing: 1,
+        })
+      end
+
+      let!(:relet_case_log) do
+        described_class.create({
+          managing_organisation: organisation,
+          owning_organisation: organisation,
+          first_time_property_let_as_social_housing: 0,
+        })
+      end
+
+      it "the newprop variable is correctly derived and saved as 1 for a first let vacancy reason" do
+        first_let_case_log.update!({ rsnvac: 15 })
+        record_from_db = ActiveRecord::Base.connection.execute("select newprop from case_logs where id=#{first_let_case_log.id}").to_a[0]
+        expect(record_from_db["newprop"]).to eq(1)
+        expect(first_let_case_log["newprop"]).to eq(1)
+      end
+
+      it "the newprop variable is correctly derived and saved as 2 for anything that is not a first let vacancy reason" do
+        relet_case_log.update!({ rsnvac: 2 })
+        record_from_db = ActiveRecord::Base.connection.execute("select newprop from case_logs where id=#{relet_case_log.id}").to_a[0]
+        expect(record_from_db["newprop"]).to eq(2)
+        expect(relet_case_log["newprop"]).to eq(2)
+      end
+    end
   end
 
   describe "resetting invalidated fields" do