diff --git a/homeassistant/components/water_heater/significant_change.py b/homeassistant/components/water_heater/significant_change.py
new file mode 100644
index 000000000000..903c80bb714c
--- /dev/null
+++ b/homeassistant/components/water_heater/significant_change.py
@@ -0,0 +1,76 @@
+"""Helper to test significant Water Heater state changes."""
+from __future__ import annotations
+
+from typing import Any
+
+from homeassistant.const import UnitOfTemperature
+from homeassistant.core import HomeAssistant, callback
+from homeassistant.helpers.significant_change import (
+    check_absolute_change,
+    check_valid_float,
+)
+
+from . import (
+    ATTR_AWAY_MODE,
+    ATTR_CURRENT_TEMPERATURE,
+    ATTR_OPERATION_MODE,
+    ATTR_TARGET_TEMP_HIGH,
+    ATTR_TARGET_TEMP_LOW,
+    ATTR_TEMPERATURE,
+)
+
+SIGNIFICANT_ATTRIBUTES: set[str] = {
+    ATTR_CURRENT_TEMPERATURE,
+    ATTR_TEMPERATURE,
+    ATTR_TARGET_TEMP_HIGH,
+    ATTR_TARGET_TEMP_LOW,
+    ATTR_OPERATION_MODE,
+    ATTR_AWAY_MODE,
+}
+
+
+@callback
+def async_check_significant_change(
+    hass: HomeAssistant,
+    old_state: str,
+    old_attrs: dict,
+    new_state: str,
+    new_attrs: dict,
+    **kwargs: Any,
+) -> bool | None:
+    """Test if state significantly changed."""
+    if old_state != new_state:
+        return True
+
+    old_attrs_s = set(old_attrs.items())
+    new_attrs_s = set(new_attrs.items())
+    changed_attrs: set[str] = {item[0] for item in old_attrs_s ^ new_attrs_s}
+    ha_unit = hass.config.units.temperature_unit
+
+    for attr_name in changed_attrs:
+        if attr_name not in SIGNIFICANT_ATTRIBUTES:
+            continue
+
+        if attr_name in [ATTR_OPERATION_MODE, ATTR_AWAY_MODE]:
+            return True
+
+        old_attr_value = old_attrs.get(attr_name)
+        new_attr_value = new_attrs.get(attr_name)
+        if new_attr_value is None or not check_valid_float(new_attr_value):
+            # New attribute value is invalid, ignore it
+            continue
+
+        if old_attr_value is None or not check_valid_float(old_attr_value):
+            # Old attribute value was invalid, we should report again
+            return True
+
+        if ha_unit == UnitOfTemperature.FAHRENHEIT:
+            absolute_change = 1.0
+        else:
+            absolute_change = 0.5
+
+        if check_absolute_change(old_attr_value, new_attr_value, absolute_change):
+            return True
+
+    # no significant attribute change detected
+    return False
diff --git a/tests/components/water_heater/test_significant_change.py b/tests/components/water_heater/test_significant_change.py
new file mode 100644
index 000000000000..40803eea09a2
--- /dev/null
+++ b/tests/components/water_heater/test_significant_change.py
@@ -0,0 +1,96 @@
+"""Test the Water Heater significant change platform."""
+import pytest
+
+from homeassistant.components.water_heater import (
+    ATTR_AWAY_MODE,
+    ATTR_CURRENT_TEMPERATURE,
+    ATTR_OPERATION_MODE,
+    ATTR_TARGET_TEMP_HIGH,
+    ATTR_TARGET_TEMP_LOW,
+    ATTR_TEMPERATURE,
+)
+from homeassistant.components.water_heater.significant_change import (
+    async_check_significant_change,
+)
+from homeassistant.core import HomeAssistant
+from homeassistant.util.unit_system import (
+    METRIC_SYSTEM as METRIC,
+    US_CUSTOMARY_SYSTEM as IMPERIAL,
+    UnitSystem,
+)
+
+
+async def test_significant_state_change(hass: HomeAssistant) -> None:
+    """Detect Water Heater significant state changes."""
+    attrs = {}
+    assert not async_check_significant_change(hass, "on", attrs, "on", attrs)
+    assert async_check_significant_change(hass, "on", attrs, "off", attrs)
+
+
+@pytest.mark.parametrize(
+    ("unit_system", "old_attrs", "new_attrs", "expected_result"),
+    [
+        (METRIC, {ATTR_AWAY_MODE: "old_value"}, {ATTR_AWAY_MODE: "old_value"}, False),
+        (METRIC, {ATTR_AWAY_MODE: "old_value"}, {ATTR_AWAY_MODE: "new_value"}, True),
+        (
+            METRIC,
+            {ATTR_OPERATION_MODE: "old_value"},
+            {ATTR_OPERATION_MODE: "new_value"},
+            True,
+        ),
+        # multiple attributes
+        (
+            METRIC,
+            {ATTR_AWAY_MODE: "old_value", ATTR_OPERATION_MODE: "old_value"},
+            {ATTR_AWAY_MODE: "new_value", ATTR_OPERATION_MODE: "old_value"},
+            True,
+        ),
+        # float attributes
+        (
+            METRIC,
+            {ATTR_CURRENT_TEMPERATURE: 50.0},
+            {ATTR_CURRENT_TEMPERATURE: 50.5},
+            True,
+        ),
+        (
+            METRIC,
+            {ATTR_CURRENT_TEMPERATURE: 50.0},
+            {ATTR_CURRENT_TEMPERATURE: 50.4},
+            False,
+        ),
+        (
+            METRIC,
+            {ATTR_CURRENT_TEMPERATURE: "invalid"},
+            {ATTR_CURRENT_TEMPERATURE: 10.0},
+            True,
+        ),
+        (
+            METRIC,
+            {ATTR_CURRENT_TEMPERATURE: 10.0},
+            {ATTR_CURRENT_TEMPERATURE: "invalid"},
+            False,
+        ),
+        (IMPERIAL, {ATTR_TEMPERATURE: 160.0}, {ATTR_TEMPERATURE: 161}, True),
+        (IMPERIAL, {ATTR_TEMPERATURE: 160.0}, {ATTR_TEMPERATURE: 160.9}, False),
+        (METRIC, {ATTR_TARGET_TEMP_HIGH: 80.0}, {ATTR_TARGET_TEMP_HIGH: 80.5}, True),
+        (METRIC, {ATTR_TARGET_TEMP_HIGH: 80.0}, {ATTR_TARGET_TEMP_HIGH: 80.4}, False),
+        (METRIC, {ATTR_TARGET_TEMP_LOW: 30.0}, {ATTR_TARGET_TEMP_LOW: 30.5}, True),
+        (METRIC, {ATTR_TARGET_TEMP_LOW: 30.0}, {ATTR_TARGET_TEMP_LOW: 30.4}, False),
+        # insignificant attributes
+        (METRIC, {"unknown_attr": "old_value"}, {"unknown_attr": "old_value"}, False),
+        (METRIC, {"unknown_attr": "old_value"}, {"unknown_attr": "new_value"}, False),
+    ],
+)
+async def test_significant_atributes_change(
+    hass: HomeAssistant,
+    unit_system: UnitSystem,
+    old_attrs: dict,
+    new_attrs: dict,
+    expected_result: bool,
+) -> None:
+    """Detect Water Heater significant attribute changes."""
+    hass.config.units = unit_system
+    assert (
+        async_check_significant_change(hass, "state", old_attrs, "state", new_attrs)
+        == expected_result
+    )