diff --git a/app/models/sales_log.rb b/app/models/sales_log.rb
index 2285aa53d..77b83e446 100644
--- a/app/models/sales_log.rb
+++ b/app/models/sales_log.rb
@@ -1,6 +1,7 @@
 class SalesLogValidator < ActiveModel::Validator
   include Validations::Sales::HouseholdValidations
   include Validations::SharedValidations
+  include Validations::Sales::FinancialValidations
 
   def validate(record)
     validation_methods = public_methods.select { |method| method.starts_with?("validate_") }
@@ -61,4 +62,8 @@ class SalesLog < Log
   def unresolved
     false
   end
+
+  def buyer_1_child?
+    ecstat1 == 9
+  end
 end
diff --git a/app/models/validations/sales/financial_validations.rb b/app/models/validations/sales/financial_validations.rb
new file mode 100644
index 000000000..a85b274b0
--- /dev/null
+++ b/app/models/validations/sales/financial_validations.rb
@@ -0,0 +1,14 @@
+module Validations::Sales::FinancialValidations
+  # Validations methods need to be called 'validate_<page_name>' to run on model save
+  # or 'validate_' to run on submit as well
+
+  def validate_income1(record)
+    if record.ecstat1 && record.income1 && record.ownershipsch == 1
+      if record.buyer_1_child? && record.income1.positive?
+        record.errors.add :income1, I18n.t("validations.financial.income1.child_income")
+      elsif record.income1 > 80_000
+        record.errors.add :income1, I18n.t("validations.financial.income1.over_hard_max", hard_max: 80_000)
+      end
+    end
+  end
+end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 05a828dea..e4724af35 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -194,6 +194,9 @@ en:
         under_hard_min: "Net income cannot be less than £%{hard_min} per week given the tenant’s working situation"
         freq_missing: "Select how often the household receives income"
         earnings_missing: "Enter how much income the household has in total"
+      income1:
+        over_hard_max: "Income must be lower than £%{hard_max}"
+        child_income: "A child‘s income must be 0"
       negative_currency: "Enter an amount above 0"
       rent:
         less_than_shortfall: "Enter an amount that is more than the shortfall in basic rent"
diff --git a/spec/models/validations/sales/financial_validations_spec.rb b/spec/models/validations/sales/financial_validations_spec.rb
new file mode 100644
index 000000000..2e9c14bd6
--- /dev/null
+++ b/spec/models/validations/sales/financial_validations_spec.rb
@@ -0,0 +1,38 @@
+require "rails_helper"
+
+RSpec.describe Validations::Sales::FinancialValidations do
+  subject(:financial_validator) { validator_class.new }
+
+  let(:validator_class) { Class.new { include Validations::Sales::FinancialValidations } }
+
+  describe "income validations" do
+    let(:record) { FactoryBot.create(:sales_log, ownershipsch: 1) }
+
+    context "with shared ownership" do
+      (0..8).each do |ecstat|
+        it "adds an error when buyer 1 income is over hard max for ecstat #{ecstat}" do
+          record.income1 = 85_000
+          record.ecstat1 = ecstat
+          financial_validator.validate_income1(record)
+          expect(record.errors["income1"])
+              .to include(match I18n.t("validations.financial.income1.over_hard_max", hard_max: 80_000))
+        end
+      end
+
+      it "validates that the income is within the expected range for the tenant’s employment status" do
+        record.income1 = 75_000
+        record.ecstat1 = 1
+        financial_validator.validate_income1(record)
+        expect(record.errors["income1"]).to be_empty
+      end
+
+      it "validates income correctly if the ecstat is child" do
+        record.income1 = 1
+        record.ecstat1 = 9
+        financial_validator.validate_income1(record)
+        expect(record.errors["income1"])
+            .to include(match I18n.t("validations.financial.income1.child_income"))
+      end
+    end
+  end
+end