diff --git a/app/models/case_log.rb b/app/models/case_log.rb
index a70dff945..81bc43613 100644
--- a/app/models/case_log.rb
+++ b/app/models/case_log.rb
@@ -39,6 +39,18 @@ class CaseLogValidator < ActiveModel::Validator
     end
   end
 
+  def validate_net_income(record)
+    return unless record.tenant_economic_status && record.weekly_net_income
+
+    applicable_income_range = IncomeRange.find_by(economic_status: record.tenant_economic_status)
+    if record.weekly_net_income > applicable_income_range.hard_max
+      record.errors.add :net_income, "Net income cannot be greater than #{applicable_income_range.hard_max} given the tenant's working situation"
+    end
+    if record.weekly_net_income < applicable_income_range.hard_max
+      record.errors.add :net_income, "Net income cannot be less than #{applicable_income_range.hard_min} given the tenant's working situation"
+    end
+  end
+
   def validate(record)
     # If we've come from the form UI we only want to validate the specific fields
     # that have just been submitted. If we're submitting a log via API or Bulk Upload
@@ -94,6 +106,19 @@ class CaseLog < ApplicationRecord
     status == "in_progress"
   end
 
+  def weekly_net_income
+    case net_income_frequency
+    when "Weekly"
+      net_income
+    when "Monthly"
+      net_income / 4
+    when "Yearly"
+      net_income / 12
+    else
+      nil
+    end
+  end
+
 private
 
   def update_status!
diff --git a/db/migrate/20211022122436_change_field_types.rb b/db/migrate/20211022122436_change_field_types.rb
new file mode 100644
index 000000000..b5b09ca53
--- /dev/null
+++ b/db/migrate/20211022122436_change_field_types.rb
@@ -0,0 +1,9 @@
+class ChangeFieldTypes < ActiveRecord::Migration[6.1]
+  def up
+    change_column :case_logs, :net_income, "integer USING CAST(property_number_of_times_relet AS integer)"
+  end
+
+  def down
+    change_column :case_logs, :net_income, :string
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index d2cdc5cd3..bcfd1d514 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2021_10_22_112906) do
+ActiveRecord::Schema.define(version: 2021_10_22_122436) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -112,7 +112,7 @@ ActiveRecord::Schema.define(version: 2021_10_22_112906) do
     t.string "property_major_repairs_date"
     t.integer "property_number_of_times_relet"
     t.string "property_wheelchair_accessible"
-    t.string "net_income"
+    t.integer "net_income"
     t.string "net_income_frequency"
     t.string "net_income_uc_proportion"
     t.string "housing_benefit"
diff --git a/spec/factories/income_range.rb b/spec/factories/income_range.rb
new file mode 100644
index 000000000..1bbb5a4ee
--- /dev/null
+++ b/spec/factories/income_range.rb
@@ -0,0 +1,21 @@
+FactoryBot.define do
+  factory :income_range do
+    sequence(:id) { |i| i }
+    trait :full_time do
+      economic_status { "full_time" }
+      soft_min { 143 }
+      soft_max { 730 }
+      hard_min { 90 }
+      hard_max { 1230 }
+    end
+    trait :retired do
+      economic_status { "retired" }
+      soft_min { 50 }
+      soft_max { 370 }
+      hard_min { 10 }
+      hard_max { 690 }
+    end
+    created_at { Time.zone.now }
+    updated_at { Time.zone.now }
+  end
+end
diff --git a/spec/models/case_log_spec.rb b/spec/models/case_log_spec.rb
index d3e4d74a9..2c301b5a0 100644
--- a/spec/models/case_log_spec.rb
+++ b/spec/models/case_log_spec.rb
@@ -26,6 +26,19 @@ RSpec.describe Form, type: :model do
       expect { CaseLog.create!(property_number_of_times_relet: 0) }.to raise_error(ActiveRecord::RecordInvalid)
     end
 
+    context "income ranges" do
+      let!(:income_range){ FactoryBot.create(:income_range, :full_time) }
+
+      it "validates net income maximum" do
+        expect {
+          CaseLog.create!(
+            tenant_economic_status: "full_time",
+            net_income: 5000,
+            net_income_frequency: "Weekly"
+          ) }.to raise_error(ActiveRecord::RecordInvalid)
+      end
+    end
+
     describe "reasonable preference validation" do
       it "if given reasonable preference is yes a reason must be selected" do
         expect {