diff --git a/python/ribasim/ribasim/config.py b/python/ribasim/ribasim/config.py
index 30408fe05..d36416862 100644
--- a/python/ribasim/ribasim/config.py
+++ b/python/ribasim/ribasim/config.py
@@ -7,7 +7,7 @@
 import pandas as pd
 import pydantic
 from geopandas import GeoDataFrame
-from pydantic import ConfigDict, Field, model_validator
+from pydantic import ConfigDict, Field, NonNegativeInt, model_validator
 from shapely.geometry import Point
 
 from ribasim.geometry import BasinAreaSchema, NodeTable
@@ -87,7 +87,7 @@ class Logging(ChildModel):
 
 
 class Node(pydantic.BaseModel):
-    node_id: int
+    node_id: NonNegativeInt
     geometry: Point
     name: str = ""
     subnetwork_id: int | None = None
diff --git a/python/ribasim/ribasim/geometry/node.py b/python/ribasim/ribasim/geometry/node.py
index d77a40f99..990dd394c 100644
--- a/python/ribasim/ribasim/geometry/node.py
+++ b/python/ribasim/ribasim/geometry/node.py
@@ -16,7 +16,7 @@
 
 
 class NodeSchema(pa.SchemaModel):
-    node_id: Series[Int32]
+    node_id: Series[Int32] = pa.Field(ge=0)
     name: Series[str] = pa.Field(default="")
     node_type: Series[str] = pa.Field(default="")
     subnetwork_id: Series[pd.Int32Dtype] = pa.Field(
diff --git a/python/ribasim/ribasim/model.py b/python/ribasim/ribasim/model.py
index 2b4f195ef..68f90e812 100644
--- a/python/ribasim/ribasim/model.py
+++ b/python/ribasim/ribasim/model.py
@@ -229,23 +229,6 @@ def _children(self):
             if isinstance(getattr(self, k), ChildModel)
         }
 
-    def validate_model_node_field_ids(self):
-        raise NotImplementedError()
-
-    def validate_model_node_ids(self):
-        raise NotImplementedError()
-
-    def validate_model(self):
-        """Validate the model.
-
-        Checks:
-        - Whether the node IDs of the node_type fields are valid
-        - Whether the node IDs in the node field correspond to the node IDs on the node type fields
-        """
-
-        self.validate_model_node_field_ids()
-        self.validate_model_node_ids()
-
     @classmethod
     def read(cls, filepath: str | PathLike[str]) -> "Model":
         """Read model from TOML file."""
diff --git a/python/ribasim/tests/test_model.py b/python/ribasim/tests/test_model.py
index 3e2ed89d6..c64ba479a 100644
--- a/python/ribasim/tests/test_model.py
+++ b/python/ribasim/tests/test_model.py
@@ -7,6 +7,7 @@
 import xugrid
 from pydantic import ValidationError
 from pyproj import CRS
+from ribasim import Node
 from ribasim.config import Solver
 from ribasim.geometry.edge import NodeData
 from ribasim.input_base import esc_id
@@ -65,24 +66,12 @@ def test_exclude_unset(basic):
     assert d["solver"]["saveat"] == 86400.0
 
 
-@pytest.mark.xfail(reason="Needs implementation")
-def test_invalid_node_id(basic):
-    model = basic
-
-    # Add entry with invalid node ID
-    df = model.pump.static.df._append(
-        {"flow_rate": 1, "node_id": -1, "active": True},
-        ignore_index=True,
-    )
-    # Currently can't handle mixed NaN and None in a DataFrame
-    df = df.where(pd.notna(df), None)
-    model.pump.static.df = df
-
+def test_invalid_node_id():
     with pytest.raises(
         ValueError,
-        match=re.escape("Node IDs must be non-negative integers, got [-1]."),
+        match=r".* Input should be greater than or equal to 0 .*",
     ):
-        model.validate_model_node_field_ids()
+        Node(-1, Point(7.0, 7.0))
 
 
 @pytest.mark.xfail(reason="Should be reimplemented by the .add() API.")