diff --git a/fractal_server/app/models/security.py b/fractal_server/app/models/security.py
index 2e002a0827..e6615dc59f 100644
--- a/fractal_server/app/models/security.py
+++ b/fractal_server/app/models/security.py
@@ -110,7 +110,7 @@ class UserOAuth(SQLModel, table=True):
         foreign_key="user_settings.id", default=None
     )
     settings: Optional[UserSettings] = Relationship(
-        sa_relationship_kwargs=dict(lazy="selectin")
+        sa_relationship_kwargs=dict(lazy="selectin", cascade="all, delete")
     )
 
     class Config:
diff --git a/fractal_server/app/routes/aux/validate_user_settings.py b/fractal_server/app/routes/aux/validate_user_settings.py
index b45e8ad531..ac2c9badf6 100644
--- a/fractal_server/app/routes/aux/validate_user_settings.py
+++ b/fractal_server/app/routes/aux/validate_user_settings.py
@@ -6,9 +6,9 @@
 from fractal_server.app.db import AsyncSession
 from fractal_server.app.models import UserOAuth
 from fractal_server.app.models import UserSettings
+from fractal_server.app.user_settings import SlurmSshUserSettings
+from fractal_server.app.user_settings import SlurmSudoUserSettings
 from fractal_server.logger import set_logger
-from fractal_server.user_settings import SlurmSshUserSettings
-from fractal_server.user_settings import SlurmSudoUserSettings
 
 logger = set_logger(__name__)
 
diff --git a/fractal_server/app/schemas/user_settings.py b/fractal_server/app/schemas/user_settings.py
index 2c713124a9..00bb5cecdb 100644
--- a/fractal_server/app/schemas/user_settings.py
+++ b/fractal_server/app/schemas/user_settings.py
@@ -63,9 +63,14 @@ class UserSettingsUpdate(BaseModel):
     _slurm_user = validator("slurm_user", allow_reuse=True)(
         valstr("slurm_user")
     )
-    _slurm_accounts = validator("slurm_accounts", allow_reuse=True)(
-        val_unique_list("slurm_accounts")
-    )
+
+    @validator("slurm_accounts")
+    def slurm_accounts_validator(cls, value):
+        if value is None:
+            return value
+        for i, item in enumerate(value):
+            value[i] = valstr(f"slurm_accounts[{i}]")(item)
+        return val_unique_list("slurm_accounts")(value)
 
     @validator("cache_dir")
     def cache_dir_validator(cls, value):
diff --git a/fractal_server/user_settings.py b/fractal_server/app/user_settings.py
similarity index 97%
rename from fractal_server/user_settings.py
rename to fractal_server/app/user_settings.py
index 841e4ebef6..786dce7af3 100644
--- a/fractal_server/user_settings.py
+++ b/fractal_server/app/user_settings.py
@@ -20,6 +20,7 @@ class SlurmSshUserSettings(BaseModel):
     ssh_private_key_path: str
     ssh_tasks_dir: str
     ssh_jobs_dir: str
+    slurm_accounts: list[str]
 
 
 class SlurmSudoUserSettings(BaseModel):
diff --git a/tests/no_version/test_auth_api.py b/tests/no_version/test_auth_api.py
index 65b91c2a03..d96c7ee20e 100644
--- a/tests/no_version/test_auth_api.py
+++ b/tests/no_version/test_auth_api.py
@@ -562,7 +562,7 @@ async def test_get_and_patch_user_settings(registered_superuser_client):
         ssh_private_key_path="/tmp/fractal",
         ssh_tasks_dir="/tmp/tasks",
         # missing "ssh_jobs_dir"
-        # missing "slurm_user"
+        slurm_user="fractal",
         slurm_accounts=["foo", "bar"],
         cache_dir="/tmp/cache",
     )
@@ -572,6 +572,12 @@ async def test_get_and_patch_user_settings(registered_superuser_client):
     debug(res.json())
     assert res.status_code == 200
 
+    res = await registered_superuser_client.patch(
+        f"{PREFIX}/users/{user_id}/settings/", json=dict(slurm_accounts=["  "])
+    )
+    debug(res.json())
+    assert res.status_code == 422
+
     # Assert patch was successful
     res = await registered_superuser_client.get(
         f"{PREFIX}/users/{user_id}/settings/",
diff --git a/tests/no_version/test_delete_user.py b/tests/no_version/test_delete_user.py
index bb87baee9f..a92034bc4b 100644
--- a/tests/no_version/test_delete_user.py
+++ b/tests/no_version/test_delete_user.py
@@ -2,6 +2,7 @@
 from sqlmodel import select
 
 from fractal_server.app.models.security import UserOAuth
+from fractal_server.app.models.security import UserSettings
 from fractal_server.app.models.v1 import LinkUserProject
 from fractal_server.app.models.v2 import LinkUserProjectV2
 
@@ -54,3 +55,33 @@ async def test_delete_user(
     assert len(project_v2.user_list) == 0
     assert len(project_v1_2.user_list) == 1
     assert len(project_v2_2.user_list) == 1
+
+
+async def test_cascade_on_delete_user_settings(db):
+
+    user = UserOAuth(
+        email="user@fractal.xy",
+        hashed_password="fake_hashed_password",
+        settings=UserSettings(slurm_accounts=["account1", "account2"]),
+    )
+    db.add(user)
+    await db.commit()
+
+    await db.refresh(user)
+    user_id = user.id
+    user_settings_id = user.user_settings_id
+
+    await db.close()
+
+    user = await db.get(UserOAuth, user_id)
+    assert user is not None
+    user_settings = await db.get(UserSettings, user_settings_id)
+    assert user_settings is not None
+
+    await db.delete(user)
+    await db.commit()
+
+    user = await db.get(UserOAuth, user_id)
+    assert user is None
+    user_settings = await db.get(UserSettings, user_settings_id)
+    assert user_settings is None