diff --git a/app/models/log.rb b/app/models/log.rb
index 96896bf3d..c373accdf 100644
--- a/app/models/log.rb
+++ b/app/models/log.rb
@@ -50,6 +50,7 @@ class Log < ApplicationRecord
 
       presenter = UprnDataPresenter.new(service.result)
 
+      self.uprn_known = 1
       self.uprn_confirmed = nil
       self.address_line1 = presenter.address_line1
       self.address_line2 = presenter.address_line2
diff --git a/spec/models/lettings_log_spec.rb b/spec/models/lettings_log_spec.rb
index 6d45406b2..960be50af 100644
--- a/spec/models/lettings_log_spec.rb
+++ b/spec/models/lettings_log_spec.rb
@@ -3139,6 +3139,7 @@ RSpec.describe LettingsLog do
         .and change(lettings_log, :postcode_full).from(nil).to("POSTCODE")
         .and change(lettings_log, :uprn_confirmed).from(1).to(nil)
         .and change(lettings_log, :county).from("county").to(nil)
+        .and change(lettings_log, :uprn_known).from(nil).to(1)
       end
     end
 
diff --git a/spec/models/sales_log_spec.rb b/spec/models/sales_log_spec.rb
index 986130d3f..ed9c58ac9 100644
--- a/spec/models/sales_log_spec.rb
+++ b/spec/models/sales_log_spec.rb
@@ -558,6 +558,7 @@ RSpec.describe SalesLog, type: :model do
         .and change(sales_log, :postcode_full).from(nil).to("POSTCODE")
         .and change(sales_log, :uprn_confirmed).from(1).to(nil)
         .and change(sales_log, :county).from("county").to(nil)
+        .and change(sales_log, :uprn_known).from(nil).to(1)
       end
     end