diff --git a/app/models/case_log.rb b/app/models/case_log.rb
index 2f411021f..c0ab8bbd5 100644
--- a/app/models/case_log.rb
+++ b/app/models/case_log.rb
@@ -105,6 +105,12 @@ class CaseLogValidator < ActiveModel::Validator
     validate_other_field(record, "tenancy_type", "other_tenancy_type")
   end
 
+  # Validations methods need to be called 'validate_' to run on model save
+  include HouseholdValidations
+  include PropertyValidations
+  include FinancialValidations
+  include TenancyValidations
+
   def validate_shared_housing_rooms(record)
     unless record.property_unit_type.nil?
       if record.property_unit_type == "Bed-sit" && record.property_number_of_bedrooms != 1
@@ -135,9 +141,7 @@ class CaseLogValidator < ActiveModel::Validator
         public_send("validate_#{question_to_validate}", record)
       end
     else
-      # This assumes that all methods in this class other than this one are
-      # validations to be run
-      validation_methods = public_methods(false) - [__callee__]
+      validation_methods = public_methods.select { |method| method.starts_with?("validate_") }
       validation_methods.each { |meth| public_send(meth, record) }
     end
   end
@@ -155,14 +159,6 @@ private
       record.errors.add other_field.to_sym, "#{other_field_label} must not be provided if #{main_field_label} was not other"
     end
   end
-
-  def women_of_child_bearing_age_in_household(record)
-    (1..8).any? do |n|
-      next if record["person_#{n}_gender"].nil? || record["person_#{n}_age"].nil?
-
-      record["person_#{n}_gender"] == "Female" && record["person_#{n}_age"] >= 16 && record["person_#{n}_age"] <= 50
-    end
-  end
 end
 
 class CaseLog < ApplicationRecord
@@ -202,6 +198,23 @@ class CaseLog < ApplicationRecord
     status == "in_progress"
   end
 
+  def weekly_net_income
+    case net_income_frequency
+    when "Weekly"
+      net_income
+    when "Monthly"
+      ((net_income * 12) / 52.0).round(0)
+    when "Yearly"
+      (net_income / 12.0).round(0)
+    end
+  end
+
+  def applicable_income_range
+    return unless person_1_economic_status
+
+    IncomeRange::ALLOWED[person_1_economic_status.to_sym]
+  end
+
 private
 
   def update_status!
@@ -239,10 +252,15 @@ private
       dynamically_not_required << "fixed_term_tenancy"
     end
 
-    if tenancy_type != "Other"
+    unless tenancy_type == "Other"
       dynamically_not_required << "other_tenancy_type"
     end
 
+    unless net_income_known == "Yes"
+      dynamically_not_required << "net_income"
+      dynamically_not_required << "net_income_frequency"
+    end
+
     required.delete_if { |key, _value| dynamically_not_required.include?(key) }
   end
 end
diff --git a/app/models/income_range.rb b/app/models/income_range.rb
new file mode 100644
index 000000000..2d0013d33
--- /dev/null
+++ b/app/models/income_range.rb
@@ -0,0 +1,15 @@
+class IncomeRange
+  ALLOWED = {
+    "Full-time - 30 hours or more": OpenStruct.new(soft_min: 143, soft_max: 730, hard_min: 90, hard_max: 1230),
+    "Part-time - Less than 30 hours": OpenStruct.new(soft_min: 67, soft_max: 620, hard_min: 50, hard_max: 950),
+    "In government training into work, such as New Deal": OpenStruct.new(soft_min: 80, soft_max: 480, hard_min: 40, hard_max: 990),
+    "Jobseeker": OpenStruct.new(soft_min: 50, soft_max: 370, hard_min: 10, hard_max: 450),
+    "Retired": OpenStruct.new(soft_min: 50, soft_max: 380, hard_min: 10, hard_max: 690),
+    "Not seeking work": OpenStruct.new(soft_min: 53, soft_max: 540, hard_min: 10, hard_max: 890),
+    "Full-time student": OpenStruct.new(soft_min: 47, soft_max: 460, hard_min: 10, hard_max: 1300),
+    "Unable to work because of long term sick or disability": OpenStruct.new(soft_min: 54, soft_max: 460, hard_min: 10, hard_max: 820),
+    "Child under 16": OpenStruct.new(soft_min: 50, soft_max: 450, hard_min: 10, hard_max: 750),
+    "Other": OpenStruct.new(soft_min: 50, soft_max: 580, hard_min: 10, hard_max: 1040),
+    "Prefer not to say": OpenStruct.new(soft_min: 47, soft_max: 730, hard_min: 10, hard_max: 1300),
+  }.freeze
+end
diff --git a/app/validations/financial_validations.rb b/app/validations/financial_validations.rb
new file mode 100644
index 000000000..90093e134
--- /dev/null
+++ b/app/validations/financial_validations.rb
@@ -0,0 +1,36 @@
+module FinancialValidations
+  # Validations methods need to be called 'validate_' to run on model save
+  def validate_outstanding_rent_amount(record)
+    if record.outstanding_rent_or_charges == "Yes" && record.outstanding_amount.blank?
+      record.errors.add :outstanding_amount, "You must answer the oustanding amout question if you have outstanding rent or charges."
+    end
+    if record.outstanding_rent_or_charges == "No" && record.outstanding_amount.present?
+      record.errors.add :outstanding_amount, "You must not answer the oustanding amout question if you don't have outstanding rent or charges."
+    end
+  end
+
+  EMPLOYED_STATUSES = ["Full-time - 30 hours or more", "Part-time - Less than 30 hours"].freeze
+  def validate_net_income_uc_proportion(record)
+    (1..8).any? do |n|
+      economic_status = record["person_#{n}_economic_status"]
+      is_employed = EMPLOYED_STATUSES.include?(economic_status)
+      relationship = record["person_#{n}_relationship"]
+      is_partner_or_main = relationship == "Partner" || (relationship.nil? && economic_status.present?)
+      if is_employed && is_partner_or_main && record.net_income_uc_proportion == "All"
+        record.errors.add :net_income_uc_proportion, "income is from Universal Credit, state pensions or benefits cannot be All if the tenant or the partner works part or full time"
+      end
+    end
+  end
+
+  def validate_net_income(record)
+    return unless record.person_1_economic_status && record.weekly_net_income
+
+    if record.weekly_net_income > record.applicable_income_range.hard_max
+      record.errors.add :net_income, "Net income cannot be greater than #{record.applicable_income_range.hard_max} given the tenant's working situation"
+    end
+
+    if record.weekly_net_income < record.applicable_income_range.hard_min
+      record.errors.add :net_income, "Net income cannot be less than #{record.applicable_income_range.hard_min} given the tenant's working situation"
+    end
+  end
+end
diff --git a/app/validations/household_validations.rb b/app/validations/household_validations.rb
new file mode 100644
index 000000000..8ff4e684a
--- /dev/null
+++ b/app/validations/household_validations.rb
@@ -0,0 +1,68 @@
+module HouseholdValidations
+  # Validations methods need to be called 'validate_' to run on model save
+  def validate_person_1_age(record)
+    if record.person_1_age && !/^[1-9][0-9]?$|^120$/.match?(record.person_1_age.to_s)
+      record.errors.add :person_1_age, "Tenant age must be between 0 and 120"
+    end
+  end
+
+  def validate_reasonable_preference(record)
+    if record.homelessness == "No" && record.reasonable_preference == "Yes"
+      record.errors.add :reasonable_preference, "Can not be Yes if Not Homeless immediately prior to this letting has been selected"
+    elsif record.reasonable_preference == "Yes"
+      if !record.reasonable_preference_reason_homeless && !record.reasonable_preference_reason_unsatisfactory_housing && !record.reasonable_preference_reason_medical_grounds && !record.reasonable_preference_reason_avoid_hardship && !record.reasonable_preference_reason_do_not_know
+        record.errors.add :reasonable_preference_reason, "If reasonable preference is Yes, a reason must be given"
+      end
+    elsif record.reasonable_preference == "No"
+      if record.reasonable_preference_reason_homeless || record.reasonable_preference_reason_unsatisfactory_housing || record.reasonable_preference_reason_medical_grounds || record.reasonable_preference_reason_avoid_hardship || record.reasonable_preference_reason_do_not_know
+        record.errors.add :reasonable_preference_reason, "If reasonable preference is No, no reasons should be given"
+      end
+    end
+  end
+
+  def validate_other_reason_for_leaving_last_settled_home(record)
+    validate_other_field(record, "reason_for_leaving_last_settled_home", "other_reason_for_leaving_last_settled_home")
+  end
+
+  def validate_reason_for_leaving_last_settled_home(record)
+    if record.reason_for_leaving_last_settled_home == "Do not know" && record.benefit_cap_spare_room_subsidy != "Do not know"
+      record.errors.add :benefit_cap_spare_room_subsidy, "must be do not know if tenant’s main reason for leaving is do not know"
+    end
+  end
+
+  def validate_armed_forces_injured(record)
+    if (record.armed_forces == "Yes - a regular" || record.armed_forces == "Yes - a reserve") && record.armed_forces_injured.blank?
+      record.errors.add :armed_forces_injured, "You must answer the armed forces injury question if the tenant has served in the armed forces"
+    end
+
+    if (record.armed_forces == "No" || record.armed_forces == "Prefer not to say") && record.armed_forces_injured.present?
+      record.errors.add :armed_forces_injured, "You must not answer the armed forces injury question if the tenant has not served in the armed forces or prefer not to say was chosen"
+    end
+  end
+
+  def validate_armed_forces_active_response(record)
+    if record.armed_forces == "Yes - a regular" && record.armed_forces_active.blank?
+      record.errors.add :armed_forces_active, "You must answer the armed forces active question if the tenant has served as a regular in the armed forces"
+    end
+
+    if record.armed_forces != "Yes - a regular" && record.armed_forces_active.present?
+      record.errors.add :armed_forces_active, "You must not answer the armed forces active question if the tenant has not served as a regular in the armed forces"
+    end
+  end
+
+  def validate_household_pregnancy(record)
+    if (record.pregnancy == "Yes" || record.pregnancy == "Prefer not to say") && !women_of_child_bearing_age_in_household(record)
+      record.errors.add :pregnancy, "You must answer no as there are no female tenants aged 16-50 in the property"
+    end
+  end
+
+private
+
+  def women_of_child_bearing_age_in_household(record)
+    (1..8).any? do |n|
+      next if record["person_#{n}_gender"].nil? || record["person_#{n}_age"].nil?
+
+      record["person_#{n}_gender"] == "Female" && record["person_#{n}_age"] >= 16 && record["person_#{n}_age"] <= 50
+    end
+  end
+end
diff --git a/app/validations/property_validations.rb b/app/validations/property_validations.rb
new file mode 100644
index 000000000..9d40a2ee5
--- /dev/null
+++ b/app/validations/property_validations.rb
@@ -0,0 +1,8 @@
+module PropertyValidations
+  # Validations methods need to be called 'validate_' to run on model save
+  def validate_property_number_of_times_relet(record)
+    if record.property_number_of_times_relet && !/^[1-9]$|^0[1-9]$|^1[0-9]$|^20$/.match?(record.property_number_of_times_relet.to_s)
+      record.errors.add :property_number_of_times_relet, "Must be between 0 and 20"
+    end
+  end
+end
diff --git a/app/validations/tenancy_validations.rb b/app/validations/tenancy_validations.rb
new file mode 100644
index 000000000..063b4672c
--- /dev/null
+++ b/app/validations/tenancy_validations.rb
@@ -0,0 +1,20 @@
+module TenancyValidations
+  # Validations methods need to be called 'validate_' to run on model save
+  def validate_fixed_term_tenancy(record)
+    is_present = record.fixed_term_tenancy.present?
+    is_in_range = record.fixed_term_tenancy.to_i.between?(2, 99)
+    is_secure = record.tenancy_type == "Fixed term – Secure"
+    is_ast = record.tenancy_type == "Fixed term – Assured Shorthold Tenancy (AST)"
+    conditions = [
+      { condition: !(is_secure || is_ast) && is_present, error: "You must only answer the fixed term tenancy length question if the tenancy type is fixed term" },
+      { condition: is_ast && !is_in_range,  error: "Fixed term – Assured Shorthold Tenancy (AST) should be between 2 and 99 years" },
+      { condition: is_secure && (!is_in_range && is_present), error: "Fixed term – Secure should be between 2 and 99 years or not specified" },
+    ]
+
+    conditions.each { |condition| condition[:condition] ? (record.errors.add :fixed_term_tenancy, condition[:error]) : nil }
+  end
+
+  def validate_other_tenancy_type(record)
+    validate_other_field(record, "tenancy_type", "other_tenancy_type")
+  end
+end
diff --git a/config/forms/2021_2022.json b/config/forms/2021_2022.json
index f4cf447c3..9f185b120 100644
--- a/config/forms/2021_2022.json
+++ b/config/forms/2021_2022.json
@@ -1458,6 +1458,21 @@
               "header": "",
               "description": "",
               "questions": {
+                "net_income_known": {
+                  "check_answer_label": "Income known",
+                  "header": "Do you know the tenant and their partner's net income?",
+                  "hint_text": "",
+                  "type": "radio",
+                  "answer_options": {
+                    "0": "Yes",
+                    "1": "No",
+                    "2": "Tenant prefers not to say"
+                  },
+                  "conditional_for": {
+                    "net_income": ["Yes"],
+                    "net_income_frequency": ["Yes"]
+                  }
+                },
                 "net_income": {
                   "check_answer_label": "Income",
                   "header": "What is the tenant’s /and partner’s combined income after tax?",
diff --git a/db/migrate/20211028083105_change_net_income_type.rb b/db/migrate/20211028083105_change_net_income_type.rb
new file mode 100644
index 000000000..85fedcceb
--- /dev/null
+++ b/db/migrate/20211028083105_change_net_income_type.rb
@@ -0,0 +1,9 @@
+class ChangeNetIncomeType < 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/migrate/20211028095000_add_net_income_known_field.rb b/db/migrate/20211028095000_add_net_income_known_field.rb
new file mode 100644
index 000000000..89e82c29f
--- /dev/null
+++ b/db/migrate/20211028095000_add_net_income_known_field.rb
@@ -0,0 +1,7 @@
+class AddNetIncomeKnownField < ActiveRecord::Migration[6.1]
+  def change
+    change_table :case_logs, bulk: true do |t|
+      t.column :net_income_known, :string
+    end
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 346f047c2..5c4ffd1ea 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_27_123535) do
+ActiveRecord::Schema.define(version: 2021_10_28_095000) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -86,7 +86,7 @@ ActiveRecord::Schema.define(version: 2021_10_27_123535) 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"
@@ -133,6 +133,7 @@ ActiveRecord::Schema.define(version: 2021_10_27_123535) do
     t.boolean "reasonable_preference_reason_do_not_know"
     t.datetime "discarded_at"
     t.string "other_tenancy_type"
+    t.string "net_income_known"
     t.index ["discarded_at"], name: "index_case_logs_on_discarded_at"
   end
 
diff --git a/docs/api/DLUHC-CORE-Data.v1.json b/docs/api/DLUHC-CORE-Data.v1.json
index 7a4d495e2..3820d9aee 100644
--- a/docs/api/DLUHC-CORE-Data.v1.json
+++ b/docs/api/DLUHC-CORE-Data.v1.json
@@ -937,6 +937,15 @@
           "property_wheelchair_accessible": {
             "type": "boolean"
           },
+          "net_income_known": {
+            "type": "string",
+            "minLength": 1,
+            "enum": [
+              "Yes",
+              "No",
+              "Tenant prefers not to say"
+            ]
+          },
           "net_income": {
             "type": "number"
           },
@@ -1208,7 +1217,8 @@
           "reasonable_preference_reason_medical_grounds",
           "reasonable_preference_reason_avoid_hardship",
           "reasonable_preference_reason_do_not_know",
-          "other_tenancy-type"
+          "other_tenancy-type",
+          "net_income_known"
         ]
       }
     },
@@ -1225,4 +1235,4 @@
       }
     }
   }
-}
\ No newline at end of file
+}
diff --git a/spec/fixtures/complete_case_log.json b/spec/fixtures/complete_case_log.json
index 9238bba6a..45e402f4e 100644
--- a/spec/fixtures/complete_case_log.json
+++ b/spec/fixtures/complete_case_log.json
@@ -68,6 +68,7 @@
       "property_major_repairs_date": "05/05/2020",
       "property_number_of_times_relet": 2,
       "property_wheelchair_accessible": true,
+      "net_income_known": "Yes",
       "net_income": 0,
       "net_income_frequency": null,
       "net_income_uc_proportion": "Some",
diff --git a/spec/models/case_log_spec.rb b/spec/models/case_log_spec.rb
index df480af78..166f377b5 100644
--- a/spec/models/case_log_spec.rb
+++ b/spec/models/case_log_spec.rb
@@ -237,10 +237,11 @@ RSpec.describe Form, type: :model do
 
       # Crossover over tests here as injured must be answered as well for no error
       it "must be answered if ever served in the forces as a regular" do
-        expect {
+        expect do
           CaseLog.create!(armed_forces: "Yes - a regular",
                           armed_forces_active: "Yes",
-                          armed_forces_injured: "Yes")}
+                          armed_forces_injured: "Yes")
+        end
       end
     end
 
@@ -269,6 +270,28 @@ RSpec.describe Form, type: :model do
         }.not_to raise_error
       end
     end
+
+    context "income ranges" do
+      it "validates net income maximum" do
+        expect {
+          CaseLog.create!(
+            person_1_economic_status: "Full-time - 30 hours or more",
+            net_income: 5000,
+            net_income_frequency: "Weekly",
+          )
+        }.to raise_error(ActiveRecord::RecordInvalid)
+      end
+
+      it "validates net income minimum" do
+        expect {
+          CaseLog.create!(
+            person_1_economic_status: "Full-time - 30 hours or more",
+            net_income: 1,
+            net_income_frequency: "Weekly",
+          )
+        }.to raise_error(ActiveRecord::RecordInvalid)
+      end
+    end
   end
 
   describe "status" do
@@ -287,4 +310,24 @@ RSpec.describe Form, type: :model do
       expect(in_progress_case_log.completed?).to be(false)
     end
   end
+
+  describe "weekly_net_income" do
+    let(:net_income) { 5000 }
+    let(:case_log) { FactoryBot.build(:case_log, net_income: net_income) }
+
+    it "returns input income if frequency is already weekly" do
+      case_log.net_income_frequency = "Weekly"
+      expect(case_log.weekly_net_income).to eq(net_income)
+    end
+
+    it "calculates the correct weekly income from monthly income" do
+      case_log.net_income_frequency = "Monthly"
+      expect(case_log.weekly_net_income).to eq(1154)
+    end
+
+    it "calculates the correct weekly income from yearly income" do
+      case_log.net_income_frequency = "Yearly"
+      expect(case_log.weekly_net_income).to eq(417)
+    end
+  end
 end
diff --git a/spec/requests/case_log_controller_spec.rb b/spec/requests/case_log_controller_spec.rb
index e6c866c90..6ddbd0130 100644
--- a/spec/requests/case_log_controller_spec.rb
+++ b/spec/requests/case_log_controller_spec.rb
@@ -115,6 +115,14 @@ RSpec.describe CaseLogsController, type: :request do
       json_response = JSON.parse(response.body)
       expect(json_response["status"]).to eq(case_log.status)
     end
+
+    context "invalid case log id" do
+      let(:id) { (CaseLog.order(:id).last&.id || 0) + 1 }
+
+      it "returns 404" do
+        expect(response).to have_http_status(:not_found)
+      end
+    end
   end
 
   describe "PATCH" do