diff --git a/homeassistant/components/sensor/__init__.py b/homeassistant/components/sensor/__init__.py
index c6c5908b5d8a04..dcdc3213edfcee 100644
--- a/homeassistant/components/sensor/__init__.py
+++ b/homeassistant/components/sensor/__init__.py
@@ -317,11 +317,19 @@ class SensorDeviceClass(StrEnum):
 
     Unit of measurement: `VOLUME_*` units
     - SI / metric: `mL`, `L`, `m³`
-    - USCS / imperial: `fl. oz.`, `gal`, `ft³` (warning: volumes expressed in
+    - USCS / imperial: `fl. oz.`, `ft³`, `gal` (warning: volumes expressed in
+    USCS/imperial units are currently assumed to be US volumes)
+    """
+
+    WATER = "water"
+    """Water.
+
+    Unit of measurement:
+    - SI / metric: `m³`, `L`
+    - USCS / imperial: `ft³`, `gal` (warning: volumes expressed in
     USCS/imperial units are currently assumed to be US volumes)
     """
 
-    # weight/mass (g, kg, mg, µg, oz, lb)
     WEIGHT = "weight"
     """Generic weight, represents a measurement of an object's mass.
 
@@ -374,6 +382,7 @@ class SensorStateClass(StrEnum):
     SensorDeviceClass.SPEED: SpeedConverter,
     SensorDeviceClass.TEMPERATURE: TemperatureConverter,
     SensorDeviceClass.VOLUME: VolumeConverter,
+    SensorDeviceClass.WATER: VolumeConverter,
     SensorDeviceClass.WEIGHT: MassConverter,
 }
 
diff --git a/homeassistant/components/sensor/device_condition.py b/homeassistant/components/sensor/device_condition.py
index 6abd0bfbfaa600..c1015636d409ff 100644
--- a/homeassistant/components/sensor/device_condition.py
+++ b/homeassistant/components/sensor/device_condition.py
@@ -63,6 +63,7 @@
 CONF_IS_VOLATILE_ORGANIC_COMPOUNDS = "is_volatile_organic_compounds"
 CONF_IS_VOLTAGE = "is_voltage"
 CONF_IS_VOLUME = "is_volume"
+CONF_IS_WATER = "is_water"
 CONF_IS_WEIGHT = "is_weight"
 
 ENTITY_CONDITIONS = {
@@ -101,6 +102,7 @@
     ],
     SensorDeviceClass.VOLTAGE: [{CONF_TYPE: CONF_IS_VOLTAGE}],
     SensorDeviceClass.VOLUME: [{CONF_TYPE: CONF_IS_VOLUME}],
+    SensorDeviceClass.WATER: [{CONF_TYPE: CONF_IS_WATER}],
     SensorDeviceClass.WEIGHT: [{CONF_TYPE: CONF_IS_WEIGHT}],
     DEVICE_CLASS_NONE: [{CONF_TYPE: CONF_IS_VALUE}],
 }
diff --git a/homeassistant/components/sensor/device_trigger.py b/homeassistant/components/sensor/device_trigger.py
index 675a59ef78d08d..c2cda7d8e9d36a 100644
--- a/homeassistant/components/sensor/device_trigger.py
+++ b/homeassistant/components/sensor/device_trigger.py
@@ -62,6 +62,7 @@
 CONF_VOLATILE_ORGANIC_COMPOUNDS = "volatile_organic_compounds"
 CONF_VOLTAGE = "voltage"
 CONF_VOLUME = "volume"
+CONF_WATER = "water"
 CONF_WEIGHT = "weight"
 
 ENTITY_TRIGGERS = {
@@ -100,6 +101,7 @@
     ],
     SensorDeviceClass.VOLTAGE: [{CONF_TYPE: CONF_VOLTAGE}],
     SensorDeviceClass.VOLUME: [{CONF_TYPE: CONF_VOLUME}],
+    SensorDeviceClass.WATER: [{CONF_TYPE: CONF_WATER}],
     SensorDeviceClass.WEIGHT: [{CONF_TYPE: CONF_WEIGHT}],
     DEVICE_CLASS_NONE: [{CONF_TYPE: CONF_VALUE}],
 }
diff --git a/homeassistant/components/sensor/strings.json b/homeassistant/components/sensor/strings.json
index 3584777bb5fc2f..12c902816b1f34 100644
--- a/homeassistant/components/sensor/strings.json
+++ b/homeassistant/components/sensor/strings.json
@@ -33,6 +33,7 @@
       "is_volatile_organic_compounds": "Current {entity_name} volatile organic compounds concentration level",
       "is_voltage": "Current {entity_name} voltage",
       "is_volume": "Current {entity_name} volume",
+      "is_water": "Current {entity_name} water",
       "is_weight": "Current {entity_name} weight"
     },
     "trigger_type": {
@@ -67,6 +68,7 @@
       "volatile_organic_compounds": "{entity_name} volatile organic compounds concentration changes",
       "voltage": "{entity_name} voltage changes",
       "volume": "{entity_name} volume changes",
+      "water": "{entity_name} water changes",
       "weight": "{entity_name} weight changes"
     }
   },
diff --git a/homeassistant/components/sensor/translations/en.json b/homeassistant/components/sensor/translations/en.json
index 1eeb31aa15c366..7fbb6e4a336442 100644
--- a/homeassistant/components/sensor/translations/en.json
+++ b/homeassistant/components/sensor/translations/en.json
@@ -32,6 +32,7 @@
             "is_volatile_organic_compounds": "Current {entity_name} volatile organic compounds concentration level",
             "is_voltage": "Current {entity_name} voltage",
             "is_volume": "Current {entity_name} volume",
+            "is_water": "Current {entity_name} water",
             "is_weight": "Current {entity_name} weight"
         },
         "trigger_type": {
@@ -66,6 +67,7 @@
             "volatile_organic_compounds": "{entity_name} volatile organic compounds concentration changes",
             "voltage": "{entity_name} voltage changes",
             "volume": "{entity_name} volume changes",
+            "water": "{entity_name} water changes",
             "weight": "{entity_name} weight changes"
         }
     },