diff --git a/alembic/versions/2a6e6975cd72_remove_uniqueness_from_ml_id_for_site_.py b/alembic/versions/2a6e6975cd72_remove_uniqueness_from_ml_id_for_site_.py
new file mode 100644
index 0000000..d1e171d
--- /dev/null
+++ b/alembic/versions/2a6e6975cd72_remove_uniqueness_from_ml_id_for_site_.py
@@ -0,0 +1,39 @@
+"""Remove uniqueness from ml id for site table
+
+Revision ID: 2a6e6975cd72
+Revises: 34891d466985
+Create Date: 2024-09-20 15:23:59.973409
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision = '2a6e6975cd72'
+down_revision = '34891d466985'
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.alter_column('sites', 'ml_id',
+               existing_type=sa.INTEGER(),
+               comment='Auto-incrementing integer ID of the site for use in ML training',
+               existing_nullable=False,
+               autoincrement=True)
+    op.drop_constraint('sites_ml_id_key', 'sites', type_='unique')
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_unique_constraint('sites_ml_id_key', 'sites', ['ml_id'])
+    op.alter_column('sites', 'ml_id',
+               existing_type=sa.INTEGER(),
+               comment=None,
+               existing_comment='Auto-incrementing integer ID of the site for use in ML training',
+               existing_nullable=False,
+               autoincrement=True)
+    # ### end Alembic commands ###
diff --git a/poetry.lock b/poetry.lock
index 8c894e4..00bec0e 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1,4 +1,4 @@
-# This file is automatically @generated by Poetry 1.8.2 and should not be changed by hand.
+# This file is automatically @generated by Poetry 1.8.3 and should not be changed by hand.
 
 [[package]]
 name = "alembic"
@@ -1470,4 +1470,4 @@ files = [
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.11"
-content-hash = "f7e4ba9700ecfa7286bc318f3a1e9946a3ae683947531537ec1b90ef8df90c39"
+content-hash = "1bdab9016adf485c3a8a1da6a25cb47847f08a127ee6f4ca56e4753079a8871b"
diff --git a/pvsite_datamodel/sqlmodels.py b/pvsite_datamodel/sqlmodels.py
index 4577f11..d411d5b 100644
--- a/pvsite_datamodel/sqlmodels.py
+++ b/pvsite_datamodel/sqlmodels.py
@@ -165,7 +165,6 @@ class SiteSQL(Base, CreatedMixin):
         sa.Integer,
         autoincrement=True,
         nullable=False,
-        unique=True,
         comment="Auto-incrementing integer ID of the site for use in ML training",
     )
 
diff --git a/pvsite_datamodel/write/user_and_site.py b/pvsite_datamodel/write/user_and_site.py
index 0449613..dfbeb3e 100644
--- a/pvsite_datamodel/write/user_and_site.py
+++ b/pvsite_datamodel/write/user_and_site.py
@@ -74,6 +74,7 @@ def create_site(
     tilt: Optional[float] = None,
     inverter_capacity_kw: Optional[float] = None,
     module_capacity_kw: Optional[float] = None,
+    ml_id: Optional[int] = None,
 ) -> [SiteSQL, str]:
     """
     Create a site and adds it to the database.
@@ -93,6 +94,7 @@ def create_site(
     :param tilt: tilt of site, default is 35
     :param inverter_capacity_kw: inverter capacity of site in kw
     :param module_capacity_kw: module capacity of site in kw
+    :param ml_id: internal ML modelling id
 
     """
     max_ml_id = session.query(func.max(SiteSQL.ml_id)).scalar()
@@ -133,7 +135,7 @@ def create_site(
         dno = json.dumps(dno)
 
     site = SiteSQL(
-        ml_id=max_ml_id + 1,
+        ml_id=ml_id if ml_id else max_ml_id + 1,
         client_site_id=client_site_id,
         client_site_name=client_site_name,
         latitude=latitude,
diff --git a/tests/test_write.py b/tests/test_write.py
index fa7d1d5..d66e789 100644
--- a/tests/test_write.py
+++ b/tests/test_write.py
@@ -203,6 +203,34 @@ def test_create_new_site_twice(db_session):
     assert site_2.ml_id == 2
 
 
+# test for create_site to check ml_id duplicates are allowed for separate clients
+def test_ml_id_duplicate_for_unique_clients(db_session):
+    """Test create sites with duplicate ml_id for different clients"""
+
+    site_1, _ = create_site(
+        session=db_session,
+        client_site_id=6932,
+        client_site_name="test_site_name_1",
+        latitude=1.0,
+        longitude=1.0,
+        capacity_kw=1.0,
+        ml_id=1,
+    )
+
+    site_2, _ = create_site(
+        session=db_session,
+        client_site_id=6933,
+        client_site_name="test_site_name_2",
+        latitude=1.0,
+        longitude=1.0,
+        capacity_kw=1.0,
+        ml_id=1,
+    )
+
+    assert site_1.ml_id == 1
+    assert site_2.ml_id == 1
+
+
 def test_create_user(db_session):
     "Test to create a new user."