diff --git a/RELEASE_NOTES.rst b/RELEASE_NOTES.rst
index acbb91bd..6b991c7b 100644
--- a/RELEASE_NOTES.rst
+++ b/RELEASE_NOTES.rst
@@ -17,6 +17,14 @@ Upcoming Release
    To use the features already you have to install the ``master`` branch, e.g.
    ``pip install git+https://github.com/pypsa/atlite``.
 
+**Bug fixes**
+
+* Fix ``ExclusionContainer.add_raster`` ignoring ``codes=0``. The code ``0`` was
+  treated like a missing ``codes`` argument, so all non-zero cells were excluded
+  instead of the cells with value ``0``. Numpy arrays are now accepted as
+  ``codes``, and an empty list excludes no cells
+  (https://github.com/PyPSA/atlite/pull/525).
+
 `v0.7.0 <https://github.com/PyPSA/atlite/releases/tag/v0.7.0>`__ (3rd October 2026)
 =======================================================================================
 
diff --git a/atlite/gis.py b/atlite/gis.py
index 21efc60e..7e2286a0 100644
--- a/atlite/gis.py
+++ b/atlite/gis.py
@@ -459,7 +459,7 @@ def shape_availability(
             masked, transform = projected_mask(
                 d["raster"], geometry, transform, shape, excluder.crs, **kwargs
             )
-        if d["codes"]:
+        if d["codes"] is not None:
             if callable(d["codes"]):
                 masked_ = d["codes"](masked).astype(bool)
             else:
@@ -598,7 +598,7 @@ def add_raster(
             which takes the mask (np.array) as argument and performs a
             elementwise condition (must not change the shape). The function may
             not be an anonymous (lambda) function.
-            The default is 1.
+            The default is None, which excludes all non-zero cells.
         buffer : int, optional
             Buffer around the excluded areas in units of ExclusionContainer.crs.
             Use this to create a buffer around the excluded/included area.
diff --git a/test/test_gis.py b/test/test_gis.py
index 89210b33..e19a0d50 100755
--- a/test/test_gis.py
+++ b/test/test_gis.py
@@ -636,6 +636,23 @@ def test_shape_availability_exclude_raster_codes(ref, raster_codes):
     assert ratio == masked.sum() / masked.size
 
 
+@pytest.mark.parametrize("codes", [0, np.array([0])])
+def test_shape_availability_exclude_raster_code_zero(ref, raster, codes):
+    """Code 0 is excluded like any other code, not treated as a missing code."""
+    shapes = gpd.GeoSeries([box(X0, Y0, X1, Y1)], crs=ref.crs)
+    res = 0.01
+
+    excluder = ExclusionContainer(ref.crs, res=res)
+    excluder.add_raster(raster, codes=[0])
+    expected, transform = shape_availability(shapes, excluder)
+
+    excluder = ExclusionContainer(ref.crs, res=res)
+    excluder.add_raster(raster, codes=codes)
+    masked, transform = shape_availability(shapes, excluder)
+    assert (masked == expected).all()
+    assert round(masked.sum() / masked.size, 2) == raster_clip
+
+
 def test_plot_shape_availability(ref, raster):
     """Test plotting of shape availability."""
     shapes = gpd.GeoSeries([box(X0, Y0, X1, Y1)], crs=ref.crs)