diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 357a299..fa12a1d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -103,6 +103,21 @@ jobs:
           npm ci
           npm install -g mjml
 
+      - name: Purge postgres 
+        run: |
+          sudo apt-get --purge remove postgresql postgresql-*
+      
+      - name: Upgrade packages
+        run: |
+          sudo apt-get update && sudo apt-get upgrade
+      - name: Install Postgresql/PostGIS 12
+        run: |
+          sudo apt-get install postgresql-12 postgresql-12-postgis-3
+      - name: Setup and start postgres service
+        run: |
+          sudo pg_ctlcluster 12 main start
+          sudo -u ${POSTGRES_USER} psql -p ${POSTGRES_PORT} -c "ALTER USER ${POSTGRES_USER} WITH PASSWORD '${POSTGRES_PASSWORD}';"
+
       - name: Set up Django
         run: |
           python manage.py migrate
diff --git a/mycarehub/clients/models.py b/mycarehub/clients/models.py
index 86a5f36..1dcc5bb 100644
--- a/mycarehub/clients/models.py
+++ b/mycarehub/clients/models.py
@@ -1,5 +1,6 @@
 from django.contrib.auth import get_user_model
 from django.contrib.postgres.fields import ArrayField
+from django.core.exceptions import ValidationError
 from django.db import models
 from django.db.models.enums import TextChoices
 from django.utils import timezone
@@ -98,6 +99,8 @@ class IdentifierUse(models.TextChoices):
     valid_to = models.DateTimeField(null=True, blank=True)
     is_primary_identifier = models.BooleanField(default=False)
 
+    model_validators = ["validate_if_identifier_value_exists"]
+
     def __str__(self):
         return f"{self.identifier_value} ({self.identifier_type}, {self.identifier_use})"
 
@@ -107,6 +110,22 @@ class Meta(AbstractBase.Meta):
             "identifier_value",
         )
 
+    def validate_if_identifier_value_exists(self):
+        if Identifier.objects.filter(
+            identifier_value=self.identifier_value,
+            identifier_type=self.identifier_type,
+        ).exists():
+            raise ValidationError(
+                _(
+                    "Identifier value %(identifier_value)s of "
+                    "type %(identifier_type)s already exists"
+                ),
+                params={
+                    "identifier_value": self.identifier_value,
+                    "identifier_type": self.identifier_type,
+                },
+            )
+
 
 @register_snippet
 class SecurityQuestion(AbstractBase):
diff --git a/mycarehub/clients/tests/test_models.py b/mycarehub/clients/tests/test_models.py
index 5de925f..1e961b0 100644
--- a/mycarehub/clients/tests/test_models.py
+++ b/mycarehub/clients/tests/test_models.py
@@ -25,6 +25,27 @@ def test_identifier_str():
     assert str(identifier) == "222 (NATIONAL_ID, OFFICIAL)"
 
 
+def test_validate_if_identifier_value_exists():
+    identifier_value = "111"
+    identifier_type = "NATIONAL_ID"
+    identifier_use = "OFFICIAL"
+    baker.make(
+        Identifier,
+        identifier_value=identifier_value,
+        identifier_type=identifier_type,
+        identifier_use=identifier_use,
+    )
+
+    duplicate_identifier = baker.prepare(
+        Identifier,
+        identifier_value=identifier_value,
+        identifier_type=identifier_type,
+        identifier_use=identifier_use,
+    )
+    with pytest.raises(Exception):
+        duplicate_identifier.save()
+
+
 def test_related_person_str():
     related_person = baker.make(
         RelatedPerson,
diff --git a/mycarehub/clients/views.py b/mycarehub/clients/views.py
index ddb4b4c..da108f8 100644
--- a/mycarehub/clients/views.py
+++ b/mycarehub/clients/views.py
@@ -113,18 +113,17 @@ def post(self, request, format=None):
                 )
 
                 # create an identifier (CCC)
-                identifier, _ = Identifier.objects.get_or_create(
-                    identifier_value=data["ccc_number"],
-                    identifier_type="CCC",
-                    defaults={
-                        "identifier_use": "OFFICIAL",
-                        "description": "CCC Number, Primary Identifier",
-                        "is_primary_identifier": True,
-                        "organisation": org,
-                        "created_by": request_user.pk,
-                        "updated_by": request_user.pk,
-                    },
-                )
+                identifier_data = {
+                    "identifier_type": "CCC",
+                    "identifier_value": data["ccc_number"],
+                    "identifier_use": "OFFICIAL",
+                    "description": "CCC Number, Primary Identifier",
+                    "is_primary_identifier": True,
+                    "organisation": org,
+                    "created_by": request_user.pk,
+                    "updated_by": request_user.pk,
+                }
+                identifier = Identifier.objects.create(**identifier_data)
 
                 # retrieve the facility by the unique name
                 facility_name = data["facility"]