diff --git a/packages/overture-schema-common/changelog.d/696.breaking.md b/packages/overture-schema-common/changelog.d/696.breaking.md
new file mode 100644
index 000000000..d8f651e92
--- /dev/null
+++ b/packages/overture-schema-common/changelog.d/696.breaking.md
@@ -0,0 +1 @@
+Removed the `level` default of `0`; a feature parsed without a level now yields `None` instead of `0`, and the field description states that absence means visual level.
diff --git a/packages/overture-schema-common/src/overture/schema/common/level.py b/packages/overture-schema-common/src/overture/schema/common/level.py
index 14ea6f15d..6073302ad 100644
--- a/packages/overture-schema-common/src/overture/schema/common/level.py
+++ b/packages/overture-schema-common/src/overture/schema/common/level.py
@@ -20,4 +20,12 @@
 class Stacked(BaseModel):
     """Properties defining feature Z-order, i.e., stacking order."""
 
-    level: Level | None = 0  # type: ignore[assignment]
+    level: Annotated[
+        Level | None,
+        Field(
+            description=(
+                "Z-order of the feature where 0 is visual level. A feature "
+                "without a level is at visual level."
+            )
+        ),
+    ] = None
diff --git a/packages/overture-schema-theme-base/changelog.d/696.breaking.md b/packages/overture-schema-theme-base/changelog.d/696.breaking.md
new file mode 100644
index 000000000..d12a80821
--- /dev/null
+++ b/packages/overture-schema-theme-base/changelog.d/696.breaking.md
@@ -0,0 +1 @@
+Made `class` and `subtype` required on `Land` and `Water`, matching `Infrastructure` and `LandUse`; constructing either without them now raises instead of falling back to `land`/`water`.
diff --git a/packages/overture-schema-theme-base/src/overture/schema/base/land.py b/packages/overture-schema-theme-base/src/overture/schema/base/land.py
index d3119912e..4001eb075 100644
--- a/packages/overture-schema-theme-base/src/overture/schema/base/land.py
+++ b/packages/overture-schema-theme-base/src/overture/schema/base/land.py
@@ -139,10 +139,8 @@ class Land(
 
     # Required
 
-    class_: Annotated[LandClass, Field(default=LandClass.LAND, alias="class")] = (
-        LandClass.LAND
-    )
-    subtype: Annotated[LandSubtype, Field(default=LandSubtype.LAND)] = LandSubtype.LAND
+    class_: Annotated[LandClass, Field(alias="class")]
+    subtype: LandSubtype
 
     # Optional
 
diff --git a/packages/overture-schema-theme-base/src/overture/schema/base/water.py b/packages/overture-schema-theme-base/src/overture/schema/base/water.py
index fbf5ab4b9..37978a376 100644
--- a/packages/overture-schema-theme-base/src/overture/schema/base/water.py
+++ b/packages/overture-schema-theme-base/src/overture/schema/base/water.py
@@ -138,19 +138,8 @@ class Water(
 
     # Required
 
-    class_: Annotated[
-        WaterClass,
-        Field(
-            default=WaterClass.WATER,
-            alias="class",
-        ),
-    ] = WaterClass.WATER
-    subtype: Annotated[
-        WaterSubtype,
-        Field(
-            default=WaterSubtype.WATER,
-        ),
-    ] = WaterSubtype.WATER
+    class_: Annotated[WaterClass, Field(alias="class")]
+    subtype: WaterSubtype
 
     # Optional
 
diff --git a/packages/overture-schema-theme-base/tests/infrastructure_baseline_schema.json b/packages/overture-schema-theme-base/tests/infrastructure_baseline_schema.json
index 1c3336a31..b93b440bb 100644
--- a/packages/overture-schema-theme-base/tests/infrastructure_baseline_schema.json
+++ b/packages/overture-schema-theme-base/tests/infrastructure_baseline_schema.json
@@ -643,8 +643,7 @@
           "type": "number"
         },
         "level": {
-          "default": 0,
-          "description": "Z-order of the feature where 0 is visual level",
+          "description": "Z-order of the feature where 0 is visual level. A feature without a level is at visual level.",
           "maximum": 2147483647,
           "minimum": -2147483648,
           "title": "Level",
diff --git a/packages/overture-schema-theme-base/tests/land_baseline_schema.json b/packages/overture-schema-theme-base/tests/land_baseline_schema.json
index f41908d7c..7ff091acf 100644
--- a/packages/overture-schema-theme-base/tests/land_baseline_schema.json
+++ b/packages/overture-schema-theme-base/tests/land_baseline_schema.json
@@ -507,8 +507,7 @@
       },
       "properties": {
         "class": {
-          "$ref": "#/$defs/LandClass",
-          "default": "land"
+          "$ref": "#/$defs/LandClass"
         },
         "elevation": {
           "description": "Elevation above sea level of the feature in meters.",
@@ -518,8 +517,7 @@
           "type": "integer"
         },
         "level": {
-          "default": 0,
-          "description": "Z-order of the feature where 0 is visual level",
+          "description": "Z-order of the feature where 0 is visual level. A feature without a level is at visual level.",
           "maximum": 2147483647,
           "minimum": -2147483648,
           "title": "Level",
@@ -546,8 +544,7 @@
           "uniqueItems": true
         },
         "subtype": {
-          "$ref": "#/$defs/LandSubtype",
-          "default": "land"
+          "$ref": "#/$defs/LandSubtype"
         },
         "surface": {
           "$ref": "#/$defs/SurfaceMaterial"
@@ -579,7 +576,9 @@
       "required": [
         "theme",
         "type",
-        "version"
+        "version",
+        "class",
+        "subtype"
       ],
       "type": "object"
     },
diff --git a/packages/overture-schema-theme-base/tests/land_use_baseline_schema.json b/packages/overture-schema-theme-base/tests/land_use_baseline_schema.json
index e85b38189..440b2b9ca 100644
--- a/packages/overture-schema-theme-base/tests/land_use_baseline_schema.json
+++ b/packages/overture-schema-theme-base/tests/land_use_baseline_schema.json
@@ -595,8 +595,7 @@
           "type": "integer"
         },
         "level": {
-          "default": 0,
-          "description": "Z-order of the feature where 0 is visual level",
+          "description": "Z-order of the feature where 0 is visual level. A feature without a level is at visual level.",
           "maximum": 2147483647,
           "minimum": -2147483648,
           "title": "Level",
diff --git a/packages/overture-schema-theme-base/tests/water_baseline_schema.json b/packages/overture-schema-theme-base/tests/water_baseline_schema.json
index 40ca4333b..8434a41bb 100644
--- a/packages/overture-schema-theme-base/tests/water_baseline_schema.json
+++ b/packages/overture-schema-theme-base/tests/water_baseline_schema.json
@@ -468,8 +468,7 @@
       },
       "properties": {
         "class": {
-          "$ref": "#/$defs/WaterClass",
-          "default": "water"
+          "$ref": "#/$defs/WaterClass"
         },
         "is_intermittent": {
           "description": "Whether the water body exists intermittently, not permanently",
@@ -482,8 +481,7 @@
           "type": "boolean"
         },
         "level": {
-          "default": 0,
-          "description": "Z-order of the feature where 0 is visual level",
+          "description": "Z-order of the feature where 0 is visual level. A feature without a level is at visual level.",
           "maximum": 2147483647,
           "minimum": -2147483648,
           "title": "Level",
@@ -510,8 +508,7 @@
           "uniqueItems": true
         },
         "subtype": {
-          "$ref": "#/$defs/WaterSubtype",
-          "default": "water"
+          "$ref": "#/$defs/WaterSubtype"
         },
         "theme": {
           "const": "base",
@@ -540,7 +537,9 @@
       "required": [
         "theme",
         "type",
-        "version"
+        "version",
+        "class",
+        "subtype"
       ],
       "type": "object"
     },
diff --git a/packages/overture-schema-theme-buildings/changelog.d/696.breaking.md b/packages/overture-schema-theme-buildings/changelog.d/696.breaking.md
new file mode 100644
index 000000000..481c64d60
--- /dev/null
+++ b/packages/overture-schema-theme-buildings/changelog.d/696.breaking.md
@@ -0,0 +1 @@
+Buildings and building parts parsed without a `level` now yield `None` instead of `0`, following the removal of the `Stacked.level` default.
diff --git a/packages/overture-schema-theme-buildings/tests/building_baseline_schema.json b/packages/overture-schema-theme-buildings/tests/building_baseline_schema.json
index 1f629b551..2bc134246 100644
--- a/packages/overture-schema-theme-buildings/tests/building_baseline_schema.json
+++ b/packages/overture-schema-theme-buildings/tests/building_baseline_schema.json
@@ -561,8 +561,7 @@
           "type": "boolean"
         },
         "level": {
-          "default": 0,
-          "description": "Z-order of the feature where 0 is visual level",
+          "description": "Z-order of the feature where 0 is visual level. A feature without a level is at visual level.",
           "maximum": 2147483647,
           "minimum": -2147483648,
           "title": "Level",
diff --git a/packages/overture-schema-theme-buildings/tests/building_part_baseline_schema.json b/packages/overture-schema-theme-buildings/tests/building_part_baseline_schema.json
index 6617c368d..f511e30ec 100644
--- a/packages/overture-schema-theme-buildings/tests/building_part_baseline_schema.json
+++ b/packages/overture-schema-theme-buildings/tests/building_part_baseline_schema.json
@@ -444,8 +444,7 @@
           "type": "boolean"
         },
         "level": {
-          "default": 0,
-          "description": "Z-order of the feature where 0 is visual level",
+          "description": "Z-order of the feature where 0 is visual level. A feature without a level is at visual level.",
           "maximum": 2147483647,
           "minimum": -2147483648,
           "title": "Level",
diff --git a/packages/overture-schema-theme-transportation/changelog.d/696.breaking.md b/packages/overture-schema-theme-transportation/changelog.d/696.breaking.md
new file mode 100644
index 000000000..97a56be8d
--- /dev/null
+++ b/packages/overture-schema-theme-transportation/changelog.d/696.breaking.md
@@ -0,0 +1 @@
+Removed the `is_max_speed_variable` default of `False`; a rule parsed without the flag now yields `None` instead of `False`.
diff --git a/packages/overture-schema-theme-transportation/src/overture/schema/transportation/segment/_common.py b/packages/overture-schema-theme-transportation/src/overture/schema/transportation/segment/_common.py
index 03c27bbae..c922e7d9c 100644
--- a/packages/overture-schema-theme-transportation/src/overture/schema/transportation/segment/_common.py
+++ b/packages/overture-schema-theme-transportation/src/overture/schema/transportation/segment/_common.py
@@ -322,7 +322,7 @@ class SpeedLimitRule(BaseModel):
             description="Indicates a variable speed corridor",
             strict=True,
         ),
-    ] = False
+    ] = None
 
 
 SpeedLimits = NewType(
diff --git a/packages/overture-schema-theme-transportation/tests/segment_baseline_schema.json b/packages/overture-schema-theme-transportation/tests/segment_baseline_schema.json
index 3bcceda22..d7473d5ed 100644
--- a/packages/overture-schema-theme-transportation/tests/segment_baseline_schema.json
+++ b/packages/overture-schema-theme-transportation/tests/segment_baseline_schema.json
@@ -1323,7 +1323,6 @@
           "type": "array"
         },
         "is_max_speed_variable": {
-          "default": false,
           "description": "Indicates a variable speed corridor",
           "title": "Is Max Speed Variable",
           "type": "boolean"