diff --git a/app/tasks/maintenance/delete_orphaned_champs_with_missing_dossier_task.rb b/app/tasks/maintenance/delete_orphaned_champs_with_missing_dossier_task.rb
new file mode 100644
index 000000000..533eb25df
--- /dev/null
+++ b/app/tasks/maintenance/delete_orphaned_champs_with_missing_dossier_task.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+module Maintenance
+  # On our production environment, the fk between `champs.dossier_id` and `dossiers.id` had not been created
+  # this maintenance task cleans up orphaned champ pointing to deleted dossier
+  # next step is to validate the recreated fk
+  # For our own record, use it with  PG_STATEMENT_TIMEOUT=300000 ....
+  class DeleteOrphanedChampsWithMissingDossierTask < MaintenanceTasks::Task
+    def collection
+      Champ.select(:id, :type).where.missing(:dossier)
+    end
+
+    def process(champ)
+      champ.reload # in case we need more data on this champ
+
+      case champ.type
+      when 'Champs::CarteChamp' then
+        champ.geo_areas.delete_all
+      when 'Champs::RepetitionChamp' then
+        champ.champs.delete_all
+      when 'Champs::SiretChamp' then
+        etablissement = champ.etablissement
+        champ.update(etablissement_id: nil)
+        etablissement.delete
+      end
+      champ.delete
+    end
+
+    def count
+      # no count, it otherwise it will timeout
+    end
+  end
+end
diff --git a/db/migrate/20240826130121_add_missing_index_champs_to_dossier.rb b/db/migrate/20240826130121_add_missing_index_champs_to_dossier.rb
new file mode 100644
index 000000000..562cb1dc5
--- /dev/null
+++ b/db/migrate/20240826130121_add_missing_index_champs_to_dossier.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AddMissingIndexChampsToDossier < ActiveRecord::Migration[7.0]
+  def change
+    add_foreign_key :champs, :dossiers, if_not_exists: true, validate: false
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 90c1c10b2..c8fc6ebfa 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[7.0].define(version: 2024_07_29_160650) do
+ActiveRecord::Schema[7.0].define(version: 2024_08_26_130121) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_buffercache"
   enable_extension "pg_stat_statements"
diff --git a/spec/tasks/maintenance/delete_orphaned_champs_with_missing_dossier_task_spec.rb b/spec/tasks/maintenance/delete_orphaned_champs_with_missing_dossier_task_spec.rb
new file mode 100644
index 000000000..60a171e74
--- /dev/null
+++ b/spec/tasks/maintenance/delete_orphaned_champs_with_missing_dossier_task_spec.rb
@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+module Maintenance
+  RSpec.describe DeleteOrphanedChampsWithMissingDossierTask do
+    describe "#process" do
+      let(:procedure) { create(:procedure, types_de_champ_public:) }
+      let(:dossier) { create(:dossier, :with_populated_champs, procedure:) }
+      let(:champ) { dossier.champs.first }
+
+      subject(:process) { described_class.process(champ) }
+
+      context 'with other champs' do
+        let(:types_de_champ_public) { [{ type: :text }] }
+        it 'delete champ' do
+          expect { subject }.to change { Champ.exists?(champ.id) }.from(true).to(false)
+        end
+      end
+
+      context "with carte" do
+        let(:types_de_champ_public) { [{ type: :carte }] }
+        it 'deletes champ.geo_areas' do
+          geo_area_ids = champ.geo_areas.ids
+          expect { subject }.to change { GeoArea.where(id: geo_area_ids).count }.from(2).to(0)
+          expect(Champ.exists?(champ.id)).to be_falsey
+        end
+      end
+
+      context "with repetition" do
+        let(:types_de_champ_public) { [{ type: :repetition, mandatory: true, children: [{ type: :text }] }] }
+        it 'deletes champ.champs (children)' do
+          expect { subject }.to change { champ.champs.count }.from(2).to(0)
+          expect(Champ.exists?(champ.id)).to be_falsey
+        end
+      end
+
+      context "with siret" do
+        let(:types_de_champ_public) { [{ type: :siret }] }
+        it 'delete champ.etablissement' do
+          expect { subject }.to change { Etablissement.exists?(champ.etablissement_id) }.from(true).to(false)
+          expect(Champ.exists?(champ.id)).to be_falsey
+        end
+      end
+    end
+  end
+end