diff --git a/homeassistant/components/suez_water/coordinator.py b/homeassistant/components/suez_water/coordinator.py
index 72da68c0f5d..aab1ba110b7 100644
--- a/homeassistant/components/suez_water/coordinator.py
+++ b/homeassistant/components/suez_water/coordinator.py
@@ -1,9 +1,7 @@
 """Suez water update coordinator."""
 
-from collections.abc import Mapping
 from dataclasses import dataclass
 from datetime import date
-from typing import Any
 
 from pysuez import PySuezError, SuezClient
 
@@ -20,11 +18,11 @@ from .const import CONF_COUNTER_ID, DATA_REFRESH_INTERVAL, DOMAIN
 class SuezWaterAggregatedAttributes:
     """Class containing aggregated sensor extra attributes."""
 
-    this_month_consumption: dict[date, float]
-    previous_month_consumption: dict[date, float]
+    this_month_consumption: dict[str, float]
+    previous_month_consumption: dict[str, float]
     last_year_overall: dict[str, float]
     this_year_overall: dict[str, float]
-    history: dict[date, float]
+    history: dict[str, float]
     highest_monthly_consumption: float
 
 
@@ -33,7 +31,7 @@ class SuezWaterData:
     """Class used to hold all fetch data from suez api."""
 
     aggregated_value: float
-    aggregated_attr: Mapping[str, Any]
+    aggregated_attr: SuezWaterAggregatedAttributes
     price: float
 
 
@@ -68,18 +66,22 @@ class SuezWaterCoordinator(DataUpdateCoordinator[SuezWaterData]):
 
     async def _async_update_data(self) -> SuezWaterData:
         """Fetch data from API endpoint."""
+
+        def map_dict(param: dict[date, float]) -> dict[str, float]:
+            return {str(key): value for key, value in param.items()}
+
         try:
             aggregated = await self._suez_client.fetch_aggregated_data()
             data = SuezWaterData(
                 aggregated_value=aggregated.value,
-                aggregated_attr={
-                    "this_month_consumption": aggregated.current_month,
-                    "previous_month_consumption": aggregated.previous_month,
-                    "highest_monthly_consumption": aggregated.highest_monthly_consumption,
-                    "last_year_overall": aggregated.previous_year,
-                    "this_year_overall": aggregated.current_year,
-                    "history": aggregated.history,
-                },
+                aggregated_attr=SuezWaterAggregatedAttributes(
+                    this_month_consumption=map_dict(aggregated.current_month),
+                    previous_month_consumption=map_dict(aggregated.previous_month),
+                    highest_monthly_consumption=aggregated.highest_monthly_consumption,
+                    last_year_overall=aggregated.previous_year,
+                    this_year_overall=aggregated.current_year,
+                    history=map_dict(aggregated.history),
+                ),
                 price=(await self._suez_client.get_price()).price,
             )
         except PySuezError as err:
diff --git a/homeassistant/components/suez_water/sensor.py b/homeassistant/components/suez_water/sensor.py
index e4e53dd7f6d..1152ebd551b 100644
--- a/homeassistant/components/suez_water/sensor.py
+++ b/homeassistant/components/suez_water/sensor.py
@@ -2,8 +2,8 @@
 
 from __future__ import annotations
 
-from collections.abc import Callable, Mapping
-from dataclasses import dataclass
+from collections.abc import Callable
+from dataclasses import asdict, dataclass
 from typing import Any
 
 from pysuez.const import ATTRIBUTION
@@ -28,7 +28,7 @@ class SuezWaterSensorEntityDescription(SensorEntityDescription):
     """Describes Suez water sensor entity."""
 
     value_fn: Callable[[SuezWaterData], float | str | None]
-    attr_fn: Callable[[SuezWaterData], Mapping[str, Any] | None] = lambda _: None
+    attr_fn: Callable[[SuezWaterData], dict[str, Any] | None] = lambda _: None
 
 
 SENSORS: tuple[SuezWaterSensorEntityDescription, ...] = (
@@ -38,7 +38,7 @@ SENSORS: tuple[SuezWaterSensorEntityDescription, ...] = (
         native_unit_of_measurement=UnitOfVolume.LITERS,
         device_class=SensorDeviceClass.WATER,
         value_fn=lambda suez_data: suez_data.aggregated_value,
-        attr_fn=lambda suez_data: suez_data.aggregated_attr,
+        attr_fn=lambda suez_data: asdict(suez_data.aggregated_attr),
     ),
     SuezWaterSensorEntityDescription(
         key="water_price",
@@ -93,6 +93,6 @@ class SuezWaterSensor(CoordinatorEntity[SuezWaterCoordinator], SensorEntity):
         return self.entity_description.value_fn(self.coordinator.data)
 
     @property
-    def extra_state_attributes(self) -> Mapping[str, Any] | None:
+    def extra_state_attributes(self) -> dict[str, Any] | None:
         """Return extra state of the sensor."""
         return self.entity_description.attr_fn(self.coordinator.data)
diff --git a/tests/components/suez_water/conftest.py b/tests/components/suez_water/conftest.py
index f634a053c65..b034d9b00fa 100644
--- a/tests/components/suez_water/conftest.py
+++ b/tests/components/suez_water/conftest.py
@@ -1,6 +1,7 @@
 """Common fixtures for the Suez Water tests."""
 
 from collections.abc import Generator
+from datetime import date
 from unittest.mock import AsyncMock, patch
 
 from pysuez import AggregatedData, PriceResult
@@ -56,22 +57,22 @@ def mock_suez_client() -> Generator[AsyncMock]:
         result = AggregatedData(
             value=160,
             current_month={
-                "2024-01-01": 130,
-                "2024-01-02": 145,
+                date.fromisoformat("2024-01-01"): 130,
+                date.fromisoformat("2024-01-02"): 145,
             },
             previous_month={
-                "2024-12-01": 154,
-                "2024-12-02": 166,
+                date.fromisoformat("2024-12-01"): 154,
+                date.fromisoformat("2024-12-02"): 166,
             },
             current_year=1500,
             previous_year=1000,
             attribution=ATTRIBUTION,
             highest_monthly_consumption=2558,
             history={
-                "2024-01-01": 130,
-                "2024-01-02": 145,
-                "2024-12-01": 154,
-                "2024-12-02": 166,
+                date.fromisoformat("2024-01-01"): 130,
+                date.fromisoformat("2024-01-02"): 145,
+                date.fromisoformat("2024-12-01"): 154,
+                date.fromisoformat("2024-12-02"): 166,
             },
         )
 
diff --git a/tests/components/suez_water/test_sensor.py b/tests/components/suez_water/test_sensor.py
index cb578432f62..950d5d8393d 100644
--- a/tests/components/suez_water/test_sensor.py
+++ b/tests/components/suez_water/test_sensor.py
@@ -1,5 +1,6 @@
 """Test Suez_water sensor platform."""
 
+from datetime import date
 from unittest.mock import AsyncMock, patch
 
 from freezegun.api import FrozenDateTimeFactory
@@ -32,6 +33,13 @@ async def test_sensors_valid_state(
     assert mock_config_entry.state is ConfigEntryState.LOADED
     await snapshot_platform(hass, entity_registry, snapshot, mock_config_entry.entry_id)
 
+    state = hass.states.get("sensor.suez_mock_device_water_usage_yesterday")
+    assert state
+    previous: dict = state.attributes["previous_month_consumption"]
+    assert previous
+    assert previous.get(date.fromisoformat("2024-12-01")) is None
+    assert previous.get(str(date.fromisoformat("2024-12-01"))) == 154
+
 
 @pytest.mark.parametrize("method", [("fetch_aggregated_data"), ("get_price")])
 async def test_sensors_failed_update(