diff --git a/app/models/validations/household_validations.rb b/app/models/validations/household_validations.rb
index f188c4bc6..b5878cd84 100644
--- a/app/models/validations/household_validations.rb
+++ b/app/models/validations/household_validations.rb
@@ -45,7 +45,7 @@ module Validations::HouseholdValidations
     (2..8).each do |n|
       validate_person_age_matches_economic_status(record, n)
       validate_person_age_matches_relationship(record, n)
-      validate_person_age_and_relationship_matches_economic_status(record, n)
+      shared_validate_person_age_and_relationship_matches_economic_status(record, n)
     end
     shared_validate_partner_count(record, 8)
   end
@@ -170,38 +170,10 @@ private
     end
   end
 
-  def validate_person_age_and_relationship_matches_economic_status(record, person_num)
-    age = record.public_send("age#{person_num}")
-    economic_status = record.public_send("ecstat#{person_num}")
-    relationship = record.public_send("relat#{person_num}")
-    return unless age && economic_status && relationship
-
-    if age >= 16 && age <= 19 && tenant_is_child?(relationship) && (!tenant_is_fulltime_student?(economic_status) && !tenant_economic_status_refused?(economic_status))
-      record.errors.add "ecstat#{person_num}", I18n.t("validations.household.ecstat.student_16_19", person_num:)
-      record.errors.add "age#{person_num}", I18n.t("validations.household.age.student_16_19", person_num:)
-      record.errors.add "relat#{person_num}", I18n.t("validations.household.relat.student_16_19", person_num:)
-    end
-  end
-
-  def validate_partner_count(record)
-    partner_count = (2..8).count { |n| tenant_is_partner?(record["relat#{n}"]) }
-    if partner_count > 1
-      record.errors.add :base, I18n.t("validations.household.relat.one_partner")
-    end
-  end
-
   def tenant_is_economic_child?(economic_status)
     economic_status == 9
   end
 
-  def tenant_is_fulltime_student?(economic_status)
-    economic_status == 7
-  end
-
-  def tenant_economic_status_refused?(economic_status)
-    economic_status == 10
-  end
-
   def tenant_is_child?(relationship)
     relationship == "C"
   end
diff --git a/app/models/validations/sales/household_validations.rb b/app/models/validations/sales/household_validations.rb
index da6c547e5..2998c0059 100644
--- a/app/models/validations/sales/household_validations.rb
+++ b/app/models/validations/sales/household_validations.rb
@@ -9,11 +9,33 @@ module Validations::Sales::HouseholdValidations
     end
   end
 
-
   def validate_household_number_of_other_members(record)
     (2..6).each do |n|
-
+      validate_person_age_matches_relationship(record, n)
+      shared_validate_person_age_and_relationship_matches_economic_status(record, n)
     end
     shared_validate_partner_count(record, 6)
   end
+
+private
+
+  def validate_person_age_matches_relationship(record, person_num)
+    age = record.public_send("age#{person_num}")
+    relationship = record.public_send("relat#{person_num}")
+    return unless age && relationship
+
+    if age < 16 && person_is_partner?(relationship)
+      record.errors.add "relat#{person_num}", I18n.t("validations.household.relat.partner_under_16", person_num:)
+    elsif age >= 20 && person_is_child?(relationship)
+      record.errors.add "relat#{person_num}", I18n.t("validations.household.relat.child_over_20", person_num:)
+    end
+  end
+
+  def person_is_partner?(relationship)
+    relationship == "P"
+  end
+
+  def person_is_child?(relationship)
+    relationship == "C"
+  end
 end
diff --git a/app/models/validations/shared_validations.rb b/app/models/validations/shared_validations.rb
index e551de2fc..650980483 100644
--- a/app/models/validations/shared_validations.rb
+++ b/app/models/validations/shared_validations.rb
@@ -82,8 +82,21 @@ module Validations::SharedValidations
     end
   end
 
+  def shared_validate_person_age_and_relationship_matches_economic_status(record, person_num)
+    age = record.public_send("age#{person_num}")
+    economic_status = record.public_send("ecstat#{person_num}")
+    relationship = record.public_send("relat#{person_num}")
+    return unless age && economic_status && relationship
+
+    if age >= 16 && age <= 19 && person_is_child?(relationship) && (!person_is_fulltime_student?(economic_status) && !person_economic_status_refused?(economic_status))
+      record.errors.add "ecstat#{person_num}", I18n.t("validations.household.ecstat.student_16_19", person_num:)
+      record.errors.add "age#{person_num}", I18n.t("validations.household.age.student_16_19", person_num:)
+      record.errors.add "relat#{person_num}", I18n.t("validations.household.relat.student_16_19", person_num:)
+    end
+  end
+
   def shared_validate_partner_count(record, max_people)
-    partner_count = (2..max_people).count { |n| tenant_is_partner?(record["relat#{n}"]) }
+    partner_count = (2..max_people).count { |n| person_is_partner?(record["relat#{n}"]) }
     if partner_count > 1
       record.errors.add :base, I18n.t("validations.household.relat.one_partner")
     end
@@ -92,7 +105,19 @@ module Validations::SharedValidations
 
 private
 
-  def tenant_is_partner?(relationship)
+  def person_is_partner?(relationship)
     relationship == "P"
   end
+
+  def person_is_child?(relationship)
+    relationship == "C"
+  end
+
+  def person_is_fulltime_student?(economic_status)
+    economic_status == 7
+  end
+
+  def person_economic_status_refused?(economic_status)
+    economic_status == 10
+  end
 end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 2bc894b0d..878d5bef4 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -308,7 +308,9 @@ en:
         retired_male: "Answer cannot be ‘retired’ as the male tenant is under 65"
         retired_female: "Answer cannot be ‘retired’ as the female tenant is under 60"
       relat:
+        partner_under_16: "Cannot be partner if the person's age is under 16"
         child_under_16: "Person’s %{person_num}’s relationship to tenant 1 must be ‘child’ as you told us they’re under 16"
+        child_over_20: "Relationship cannot be child if the person's age is 20 or over"
         one_partner: "Number of partners cannot be greater than 1"
         student_16_19: "Answer cannot be ‘child’ as you told us the person %{person_num} is between 16 and 19 and is not a full-time student"
       housingneeds_a: